![\"\"](\"https:\/\/www.vtei.cz\/wp-content\/uploads\/2019\/12\/ilustracni-fotografie-1_edit.jpg\")
<\/a>\n\u00davod<\/h2>\n
Hav\u00e1rie jadern\u00e9 elektr\u00e1rny spojen\u00e1 s\u00a0\u00fanikem invent\u00e1\u0159e jadern\u00e9ho reaktoru je v\u016fbec nejz\u00e1va\u017en\u011bj\u0161\u00ed typ mimo\u0159\u00e1dn\u00e9 ud\u00e1losti, k\u00a0jejich\u017e \u0159e\u0161en\u00ed byl syst\u00e9m p\u0159ipravenosti k\u00a0odezv\u011b na radia\u010dn\u00ed mimo\u0159\u00e1dnou ud\u00e1lost v\u00a0\u010cR zaveden [1\u20133]. V\u00a0p\u0159\u00edpad\u011b mimo\u0159\u00e1dn\u00e9 ud\u00e1losti spojen\u00e9 s\u00a0\u00fanikem invent\u00e1\u0159e reaktoru lze p\u0159edpokl\u00e1dat uvoln\u011bn\u00ed dominantn\u00ed \u010d\u00e1sti radionuklid\u016f do atmosf\u00e9ry. Radioaktivn\u00ed kontaminace se po \u00faniku do atmosf\u00e9ry \u0161\u00ed\u0159\u00ed ve form\u011b radioaktivn\u00edho mraku p\u0159edev\u0161\u00edm nav\u00e1zan\u00e1 na \u010d\u00e1stice aerosol\u016f a\u00a0v\u00a0molekul\u00e1rn\u00ed form\u011b. M\u00edra depozice radioaktivn\u00ed kontaminace z\u00a0mraku je z\u00e1visl\u00e1 na meteorologick\u00e9 situaci, p\u0159edev\u0161\u00edm na teplotn\u011b-tlakov\u00fdch podm\u00ednk\u00e1ch, a\u00a0na sr\u00e1\u017ekov\u00e9 aktivit\u011b. Obecn\u011b plat\u00ed, \u017ee nej\u00fa\u010dinn\u011bj\u0161\u00edm depozi\u010dn\u00edm procesem je vym\u00fdv\u00e1n\u00ed radioaktivn\u00edho aerosolu z\u00a0atmosf\u00e9ry de\u0161\u0165ov\u00fdmi sr\u00e1\u017ekami [4]. Z\u00e1rove\u0148 v\u0161ak nelze vylou\u010dit ani p\u0159\u00edm\u00fd \u00fanik \u010d\u00e1sti radionuklid\u016f z\u00a0invent\u00e1\u0159e reaktoru do vodote\u010d\u00ed. Z\u00a0hlediska krizov\u00e9ho \u0159\u00edzen\u00ed je kl\u00ed\u010dovou f\u00e1z\u00ed nehodov\u00e9 expozi\u010dn\u00ed situace (NES) jej\u00ed po\u010d\u00e1te\u010dn\u00ed f\u00e1ze, b\u011bhem kter\u00e9 doch\u00e1z\u00ed k\u00a0\u00faniku radionuklid\u016f z\u00a0reaktoru, sou\u010dasn\u011b b\u011bhem n\u00ed doch\u00e1z\u00ed v\u00a0nejv\u011bt\u0161\u00ed m\u00ed\u0159e k\u00a0migraci kontaminace [2, 5].<\/p>\n
Prost\u0159edkem ur\u010den\u00fdm k\u00a0pilotn\u00edmu vyhodnocen\u00ed informac\u00ed o\u00a0migraci uvoln\u011bn\u00e9 radioaktivn\u00ed kontaminace atmosf\u00e9rou a\u00a0o\u00a0jeho aktu\u00e1ln\u00ed depozici na povrchu b\u011bhem po\u010d\u00e1te\u010dn\u00ed f\u00e1ze NES jsou matematick\u00e9 modely vych\u00e1zej\u00edc\u00ed p\u0159edev\u0161\u00edm ze zdrojov\u00e9ho \u010dlenu nastal\u00e9 hav\u00e1rie (mo\u017en\u00e9 radionuklidov\u00e9 slo\u017een\u00ed \u00faniku a\u00a0jeho velikost), z\u00a0p\u0159edpov\u011bdi po\u010das\u00ed a\u00a0z\u00a0v\u00fdsledk\u016f monitorov\u00e1n\u00ed prov\u00e1d\u011bn\u00e9ho podle N\u00e1rodn\u00edho programu monitorov\u00e1n\u00ed, kter\u00e9 jsou shroma\u017e\u010fov\u00e1ny v\u00a0datov\u00e9m st\u0159edisku S\u00daJB [5]. Zohledn\u011bna je pouze vzdu\u0161n\u00e1 migrace radionuklid\u016f, matematick\u00fd model pro \u0161\u00ed\u0159en\u00ed radioaktivn\u00ed kontaminace vodn\u00edmi toky po p\u0159\u00edm\u00e9m \u00faniku do vodote\u010d\u00ed nebo po depozici z\u00a0atmosf\u00e9ry zat\u00edm nen\u00ed k\u00a0dispozici.<\/p>\n
P\u0159es vysok\u00fd stupe\u0148 sofistikovanosti matematick\u00fdch model\u016f jejich v\u00fdstupy poskytuj\u00ed sp\u00ed\u0161e r\u00e1mcov\u00fd p\u0159ehled o\u00a0deponovan\u00e9 kontaminaci. Zku\u0161enosti z\u00a0re\u00e1ln\u00fdch hav\u00e1ri\u00ed v\u00a0\u010cernobylu a\u00a0ve Fuku\u0161im\u011b ukazuj\u00ed, \u017ee p\u0159edpokladem spolehlivosti v\u00fdsledk\u016f matematick\u00fdch model\u016f je jejich okam\u017eit\u00e1 verifikace pomoc\u00ed rychle dostupn\u00fdch dopl\u0148kov\u00fdch m\u011b\u0159en\u00ed, ide\u00e1ln\u011b prov\u00e1d\u011bn\u00fdch v\u00a0on-line re\u017eimu. K\u00a0tomu dnes slou\u017e\u00ed p\u0159edev\u0161\u00edm v\u00fdsledky s\u00edt\u011b v\u010dasn\u00e9ho zji\u0161t\u011bn\u00ed (SVZ) a\u00a0s\u00ed\u0165 sampler\u016f atmosf\u00e9rick\u00fdch aerosol\u016f. S\u00ed\u0165 v\u010dasn\u00e9ho zji\u0161t\u011bn\u00ed je tvo\u0159ena 180 kontinu\u00e1ln\u011b m\u011b\u0159\u00edc\u00edmi monitory d\u00e1vkov\u00e9ho p\u0159\u00edkonu vybaven\u00fdch Geiger-Mullerov\u00fdmi detektory. \u010c\u00e1st je rozm\u00edst\u011bna v\u00a0hust\u00e9 s\u00edti v\u00a0okol\u00ed jadern\u00fdch elektr\u00e1ren, zbytek je rozm\u00edst\u011bn v\u00edcem\u00e9n\u011b rovnom\u011brn\u011b po cel\u00e9m \u00fazem\u00ed \u010cR [5].<\/p>\n M\u011b\u0159en\u00ed radioaktivn\u00edho aerosolu v\u00a0ovzdu\u0161\u00ed je prov\u00e1d\u011bno v\u00a0r\u00e1mci s\u00edt\u011b odb\u011br\u016f vzork\u016f \u017eivotn\u00edho prost\u0159ed\u00ed a\u00a0potravn\u00edho \u0159et\u011bzce [5]. V\u00a0r\u00e1mci lok\u00e1ln\u00edch monitorovac\u00edch s\u00edt\u00ed kolem jadern\u00fdch elektr\u00e1ren je rozm\u00edst\u011bno \u0161est a\u00a0sedm vzorkovac\u00edch stanic, dal\u0161\u00edch deset je sou\u010d\u00e1st\u00ed\u00a0teritori\u00e1ln\u00ed s\u00edt\u011b pokr\u00fdvaj\u00edc\u00ed \u00fazem\u00ed \u010cR [6]. Filtry jsou odeb\u00edr\u00e1ny v\u00a0intervalech p\u0159edepsan\u00fdch Vyhl\u00e1\u0161kou o\u00a0monitorov\u00e1n\u00ed radia\u010dn\u00ed situace [6] a\u00a0je v\u00a0nich stanovena aktivita gama pomoc\u00ed polovodi\u010dov\u00e9 gama spektrometrie. Za norm\u00e1ln\u00edho monitorov\u00e1n\u00ed (technick\u00fd term\u00edn pro monitorov\u00e1n\u00ed za nehavarijn\u00ed situace) je interval pro v\u00fdm\u011bnu filtr\u016f 1 t\u00fdden, za havarijn\u00edho monitorov\u00e1n\u00ed (technick\u00fd term\u00edn pro monitorovac\u00ed re\u017eim za mimo\u0159\u00e1dn\u00e9 situace) je interval v\u00fdm\u011bny aerosolov\u00fdch filtr\u016f zkr\u00e1cen na 24 hodin pro teritori\u00e1ln\u00ed s\u00ed\u0165 a\u00a0na 6 hodin pro lok\u00e1ln\u00ed s\u00edt\u011b [6]. Nov\u011b byly vyvinuty i\u00a0syst\u00e9my on-line monitorov\u00e1n\u00ed aerosol\u016f s\u00a0detektorem NaI(Tl) nebo HPGe nad filtrem v\u00a0sampleru\u00a0[7], v\u00fdsledky jejich m\u011b\u0159en\u00ed v\u0161ak zat\u00edm nejsou za\u010dlen\u011bny do syst\u00e9mu monitorov\u00e1n\u00ed radia\u010dn\u00ed situace v\u00a0\u010cR. N\u011bkter\u00e9 evropsk\u00e9 zem\u011b tak\u00e9 disponuj\u00ed syst\u00e9mem kontinu\u00e1ln\u00edho monitorov\u00e1n\u00ed gama aktivity v\u00a0\u0159\u00ed\u010dn\u00edch vod\u00e1ch, takov\u00fd syst\u00e9m v\u0161ak v\u00a0\u010cR chyb\u00ed. Za\u010dlen\u011bn\u00ed t\u011bchto syst\u00e9m\u016f do revidovan\u00e9ho N\u00e1rodn\u00edho programu monitorov\u00e1n\u00ed by v\u00a0budoucnu mohlo v\u00e9st ke zlep\u0161en\u00ed syst\u00e9mu p\u0159ipravenosti k\u00a0odezv\u011b.<\/p>\n Povrchov\u00e1 voda z\u00a0hlediska p\u0159ipravenosti k\u00a0odezv\u011b p\u0159edstavuje p\u0159edm\u011bt zvl\u00e1\u0161tn\u00edho v\u00fdznamu, nebo\u0165 51,7 % pitn\u00fdch vod v\u00a0\u010cR je pokryto z\u00a0povrchov\u00fdch zdroj\u016f\u00a0[8], kter\u00e9 jsou p\u0159i hav\u00e1rii jadern\u00e9ho za\u0159\u00edzen\u00ed radioaktivn\u00edm spadem zraniteln\u00e9. Kontaminace vodn\u00edch zdroj\u016f p\u0159edstavuje v\u00fdznamnou bezpe\u010dnostn\u00ed hrozbu st\u00e1tu [9].<\/p>\n Monitorov\u00e1n\u00ed povrchov\u00fdch vod je v \u010cR prov\u00e1d\u011bno podle po\u017eadavk\u016f\u00a0 vyhl\u00e1\u0161ky o monitorov\u00e1n\u00ed radia\u010dn\u00ed situace [6]. Odli\u0161n\u00e9 po\u017eadavky jsou stanoveny pro teritori\u00e1ln\u00ed s\u00ed\u0165 (\u00fazem\u00ed \u010cR), lok\u00e1ln\u00ed s\u00edt\u011b (are\u00e1l nebo okol\u00ed jadern\u00e9ho za\u0159\u00edzen\u00ed nebo pracovi\u0161t\u011b III., IV. kategorie) a\u00a0pro hrani\u010dn\u00ed s\u00ed\u0165 (m\u00edsto, kde voda opou\u0161t\u00ed\u00a0\u010cR). Vyhl\u00e1\u0161ka vymezuje analyzovan\u00e9 radionuklidy, \u010detnost a\u00a0citlivost anal\u00fdz pro p\u0159edepsan\u00fd po\u010det monitorovac\u00edch m\u00edst v\u00a0r\u00e1mci jednotliv\u00fdch s\u00edt\u00ed. Konkr\u00e9tn\u00ed analytick\u00e1 metoda p\u0159edeps\u00e1na nen\u00ed, N\u00e1rodn\u00ed program monitorov\u00e1n\u00ed S\u00daJB [5] ale p\u0159edepisuje toto monitorov\u00e1n\u00ed prov\u00e1d\u011bt formou odb\u011br\u016f vzork\u016f \u017eivotn\u00edho prost\u0159ed\u00ed. V\u00a0sou\u010dasn\u00e9 praxi je zavedeno monitorov\u00e1n\u00ed aktivity gama v\u00a0odebran\u00fdch vzorc\u00edch vod, prov\u00e1d\u011bn\u00e9 pomoc\u00ed laboratorn\u00ed polovodi\u010dov\u00e9 gama spektrometrie.<\/p>\n V\u00a0r\u00e1mci norm\u00e1ln\u00edho monitorov\u00e1n\u00ed jsou ve vzorc\u00edch povrchov\u00fdch vod stanovov\u00e1ny aktivity (3<\/sup>H, 90<\/sup>Sr, 137<\/sup>Cs, celkov\u00e1 objemov\u00e1 alfa a\u00a0celkov\u00e1 objemov\u00e1 beta), ov\u0161em frekvence odb\u011br\u016f je v\u0161eobecn\u011b n\u00edzk\u00e1 (1\u201312\u00d7 za rok). Za havarijn\u00ed situace je portfolio anal\u00fdz povrchov\u00fdch vod zredukov\u00e1no na stanoven\u00ed aktivity 137<\/sup>Cs a\u00a03<\/sup>H za sou\u010dasn\u00e9ho zkr\u00e1cen\u00ed intervalu odb\u011bru na 6 hodin a\u017e 1 t\u00fdden, p\u0159ib\u00fdv\u00e1 v\u0161ak po\u017eadavek na stanoven\u00ed aktivity 131<\/sup>I v\u00a0hrani\u010dn\u00edch s\u00edt\u00edch.<\/p>\n Havarijn\u00ed monitorov\u00e1n\u00ed umo\u017e\u0148uje v\u00a0p\u0159\u00edpad\u011b hav\u00e1rie jadern\u00e9 elektr\u00e1rny stanovit aktu\u00e1ln\u00ed m\u00edru zasa\u017een\u00ed povrchov\u00fdch vod jak prost\u0159ednictv\u00edm \u00faniku kontaminace p\u0159\u00edmo do vodote\u010d\u00ed (stanoven\u00edm aktivity 3<\/sup>H), tak prost\u0159ednictv\u00edm \u00faniku do atmosf\u00e9ry a\u00a0n\u00e1slednou depozic\u00ed kontaminace (stanoven\u00edm aktivity 137<\/sup>Cs). Omezen\u00edm tohoto monitorov\u00e1n\u00ed\u00a0 je velmi mal\u00fd po\u010det odb\u011brov\u00fdch bod\u016f a\u00a0relativn\u011b dlouh\u00e9 odb\u011brov\u00e9 intervaly, d\u00e1le pak problematick\u00e9 prov\u00e1d\u011bn\u00ed odb\u011br\u016f a\u00a0p\u0159epravy vzork\u016f za prob\u00edhaj\u00edc\u00ed havarijn\u00ed situace.<\/p>\n Zm\u00edn\u011bn\u00e1 omezen\u00ed by mohla vy\u0159e\u0161it zaveden\u00ed kontinu\u00e1ln\u00edho monitorov\u00e1n\u00ed gama aktivity v\u00a0\u0159\u00ed\u010dn\u00edch vod\u00e1ch. To by p\u0159ineslo ji\u017e v\u00a0pr\u016fb\u011bhu po\u010d\u00e1te\u010dn\u00ed f\u00e1ze NES dopln\u011bn\u00ed informac\u00ed o\u00a0celkov\u00e9m mno\u017estv\u00ed radioaktivn\u00ed kontaminace deponovan\u00e9 ze spadu, kter\u00e9 by m\u011blo v\u00fdznam i\u00a0pro verifikaci matematick\u00fdch model\u016f. V\u00fdvoj aktivity um\u011bl\u00fdch radionuklid\u016f v\u00a0povrchov\u00fdch a\u00a0zejm\u00e9na \u0159\u00ed\u010dn\u00edch vod\u00e1ch v\u00a0\u010dase charakterizuje pr\u016fm\u011brnou radioaktivn\u00ed kontaminaci povod\u00ed a\u00a0umo\u017e\u0148uje spolehliv\u011bj\u0161\u00ed identifikaci m\u00edsta a\u00a0m\u00edry depozice radioaktivn\u00ed kontaminace z\u00a0ovzdu\u0161\u00ed.<\/p>\n Syst\u00e9m kontinu\u00e1ln\u00edho monitorov\u00e1n\u00ed kontaminace povrchov\u00fdch vod by m\u011bl sou\u010dasn\u011b p\u0159\u00ednos i\u00a0pro ochranu zdroj\u016f pitn\u00e9 vody.<\/p>\n V\u00a0tomto \u010dl\u00e1nku je pops\u00e1n nov\u011b konstruovan\u00fd monitorovac\u00ed syst\u00e9m ur\u010den\u00fd ke kontinu\u00e1ln\u00edmu monitorov\u00e1n\u00ed gama aktivity v\u00a0povrchov\u00fdch vod\u00e1ch pro \u00fa\u010dely\u00a0pos\u00edlen\u00ed p\u0159ipravenosti k\u00a0odezv\u011b na radia\u010dn\u00ed mimo\u0159\u00e1dnou ud\u00e1lost \u010cR. Citlivost syst\u00e9mu je nastavena tak, aby syst\u00e9m spl\u0148oval legislativn\u00ed po\u017eadavky pro havarijn\u00ed monitorov\u00e1n\u00ed aktivity gama v\u00a0povrchov\u00fdch vod\u00e1ch. Aby syst\u00e9m mohl b\u00fdt za havarijn\u00ed situace p\u0159\u00ednosn\u00fd, mus\u00ed b\u00fdt jeho provoz ochr\u00e1n\u011bn p\u0159ed n\u00e1sledky hav\u00e1rie jadern\u00e9 elektr\u00e1rny, mezi kter\u00e9 pat\u0159\u00ed p\u0159edev\u0161\u00edm v\u00fdpadek obecn\u00fdch dod\u00e1vek elektrick\u00e9 energie a\u00a0v\u0161eobecn\u00e1 panika vedouc\u00ed k\u00a0chyb\u00e1m lidsk\u00e9 obsluhy p\u0159\u00edstroj\u016f. Tomu byla p\u0159i konstrukci p\u0159\u00edstroje v\u011bnov\u00e1na zvl\u00e1\u0161tn\u00ed pozornost.<\/p>\n V\u00fdvoj syst\u00e9mu je n\u00e1pln\u00ed projektu Bezpe\u010dnostn\u00edho v\u00fdzkumu Ministerstva vnitra \u010d\u00edslo VI20172020083. Prvn\u00edm d\u00edl\u010d\u00edm c\u00edlem je vyvinout stanici na monitorov\u00e1n\u00ed um\u011bl\u00e9 gama aktivity v\u00a0povrchov\u00fdch vod\u00e1ch, a\u00a0to stanici autonomn\u00ed (nez\u00e1vislou na dod\u00e1vk\u00e1ch elektrick\u00e9 energie a\u00a0na lok\u00e1ln\u00edch dodavatel\u00edch datov\u00fdch p\u0159enos\u016f), automatickou (funguj\u00edc\u00ed bez lidsk\u00e9 obsluhy) a\u00a0odolnou v\u016f\u010di poruch\u00e1m i\u00a0za extr\u00e9mn\u00edch klimatick\u00fdch a\u00a0hydrologick\u00fdch pom\u011br\u016f a\u00a0schopnou p\u0159i b\u011b\u017en\u00fdch provozn\u00edch podm\u00ednk\u00e1ch splnit po\u017eadavky vyhl\u00e1\u0161ky \u010d. 360\/2016 Sb. vzhledem k\u00a0detek\u010dn\u00edm limit\u016fm 137<\/sup>Cs, kter\u00fd je v\u0161eobecn\u011b pova\u017eov\u00e1n za optim\u00e1ln\u00ed marker radioaktivn\u00ed kontaminace p\u0159i jadern\u00e9 hav\u00e1rii. Druh\u00fdm d\u00edl\u010d\u00edm c\u00edlem projektu je pak z\u00a0n\u011bkolika monitorovac\u00edch stanic tohoto typu sestavit monitorovac\u00ed minis\u00ed\u0165 pokr\u00fdvaj\u00edc\u00ed m\u00edsta \u010cR, kter\u00e1 jsou z\u00a0hlediska zasa\u017een\u00ed radioaktivn\u00edm spadem kl\u00ed\u010dov\u00e1. Projekt je realizov\u00e1n ve spolupr\u00e1ci St\u00e1tn\u00edho \u00fastavu radia\u010dn\u00ed ochrany a\u00a0Nuvia, a.\u00a0s. Pro p\u0159ehlednost je monitorovac\u00ed stanice d\u00e1le v\u00a0textu pojmenov\u00e1v\u00e1na akronymem vych\u00e1zej\u00edc\u00edm z\u00a0jej\u00edho n\u00e1zvu v\u00a0anglick\u00e9m jazyce SAGMA (Station for Artificial Gamma Activity Measurement), monitorovac\u00ed minis\u00ed\u0165 podle stejn\u00e9ho principu akronymem SCOMO (System for Continuous Gamma Activity Monitoring).<\/p>\n V\u00fdb\u011bru konstruk\u010dn\u00ed varianty pro SAGMA p\u0159edch\u00e1zelo porovn\u00e1n\u00ed kontinu\u00e1ln\u00edch monitor\u016f aktivity gama dostupn\u00fdch v\u00a0liter\u00e1rn\u00edch zdroj\u00edch s\u00a0legislativn\u00edmi po\u017eadavky a\u00a0se zaveden\u00fdm syst\u00e9mem monitorov\u00e1n\u00ed radia\u010dn\u00ed situace v\u00a0\u010cR.<\/p>\n Literatura popisuje mnoho kontinu\u00e1ln\u00edch m\u011b\u0159i\u010d\u016f gama aktivity ur\u010den\u00fdch pro m\u011b\u0159en\u00ed v\u00a0mo\u0159sk\u00e9 vod\u011b. Prakticky v\u0161echny popsan\u00e9 varianty m\u011b\u0159\u00ed ve 4\u03c0 geometrii\u00a0\u2013 detektor je zano\u0159en do konstantn\u00ed hloubky obvykle \u010dty\u0159 a\u00a0v\u00edce metr\u016f do hlubok\u00e9 mo\u0159sk\u00e9 vody a\u00a0masa vody tak slou\u017e\u00ed sou\u010dasn\u011b jako analyzovan\u00fd vzorek i\u00a0jako st\u00edn\u011bn\u00ed. Za\u0159\u00edzen\u00ed pot\u0159ebn\u00e1 k\u00a0z\u00e1sobov\u00e1n\u00ed p\u0159\u00edstroje elektrickou energi\u00ed a\u00a0k\u00a0vyhodnocen\u00ed odezvy detektoru jsou um\u00edst\u011bna na voru pluj\u00edc\u00edm na vodn\u00ed hladin\u011b. Podle po\u017eadovan\u00e9 citlivosti p\u0159\u00edstroj\u016f jsou voleny r\u016fzn\u00e9 varianty detektor\u016f, typem detektoru je zase podm\u00edn\u011bna volba elektrick\u00e9ho nap\u00e1jen\u00ed [10\u201313].<\/p>\n Problematika kontinu\u00e1ln\u00edho m\u011b\u0159en\u00ed gama aktivity v\u00a0povrchov\u00fdch vod\u00e1ch je v\u00a0liter\u00e1rn\u00edch zdroj\u00edch pops\u00e1na pom\u011brn\u011b m\u00e1lo. Kontinu\u00e1ln\u00ed m\u011b\u0159i\u010de gama aktivity byly uvedeny do provozu v\u00a0\u0159ek\u00e1ch\u00a0n\u011bkolika zem\u00ed z\u00e1padn\u00ed Evropy po roce 1986 v\u00a0souvislosti s\u00a0\u010dernobylskou jadernou hav\u00e1ri\u00ed. Tyto p\u0159\u00edstroje jsou ve v\u011bt\u0161in\u011b p\u0159\u00edpad\u016f zalo\u017eeny na principu gama spektrometrick\u00e9ho prom\u011b\u0159ov\u00e1n\u00ed vzork\u016f vody ve st\u00edn\u011bn\u00e9 n\u00e1dob\u011b, do kter\u00e9 je vzorek vody p\u0159e\u010derp\u00e1n [14\u201317]. Pou\u017eit\u00edm st\u00edn\u011bn\u00ed je zv\u00fd\u0161ena citlivost, ov\u0161em slo\u017eit\u00e1 konstrukce vede k\u00a0tomu, \u017ee tyto p\u0159\u00edstroje prakticky nen\u00ed mo\u017en\u00e9 provozovat v\u00a0autonomn\u00edm a\u00a0automatick\u00e9m re\u017eimu. Nav\u00edc v\u011bt\u0161ina t\u011bchto p\u0159\u00edstroj\u016f nepracuje v\u00a0kontinu\u00e1ln\u00edm, ale v\u00a0semikontinu\u00e1ln\u00edm re\u017eimu (dal\u0161\u00ed vzorek je \u010derp\u00e1n k\u00a0anal\u00fdze a\u017e po odm\u011b\u0159en\u00ed p\u0159edchoz\u00edho). Casanovas a\u00a0kol.\u00a0[18] popisuje syst\u00e9m instalovan\u00fd k\u00a0monitorov\u00e1n\u00ed jadern\u00e9 elektr\u00e1rny Asc\u00f3 ve \u0160pan\u011blsku m\u011b\u0159\u00edc\u00ed v\u00a0kontinu\u00e1ln\u00edm re\u017eimu zalo\u017een\u00e9m na principu plovouc\u00edho integra\u010dn\u00edho \u010dasov\u00e9ho okna.<\/p>\n Steinmann [19] popisuje kontinu\u00e1ln\u00ed monitorovac\u00ed stanici \u0159\u00ed\u010dn\u00edch vod SARA Water System vyu\u017e\u00edvaj\u00edc\u00ed ponornou sondu ve 4\u03c0 geometrii instalovanou na dvou \u0159ek\u00e1ch ve \u0160v\u00fdcarsku. Provozov\u00e1n\u00ed tohoto syst\u00e9mu v\u00a0\u0159\u00ed\u010dn\u00edm prost\u0159ed\u00ed p\u0159in\u00e1\u0161\u00ed oproti mo\u0159sk\u00e9mu prost\u0159ed\u00ed n\u011bkolik komplikac\u00ed. Pro mo\u0159sk\u00e9 prost\u0159ed\u00ed je sice charakteristick\u00e1 vysok\u00e1 poza\u010fov\u00e1 aktivita 40<\/sup>K, tento p\u0159\u00edsp\u011bvek je ale pro ka\u017edou lokalitu prakticky konstantn\u00ed. P\u0159\u00edsp\u011bvek terestri\u00e1ln\u00ed slo\u017eky pozad\u00ed je v\u00a0mo\u0159sk\u00e9m prost\u0159ed\u00ed t\u00e9m\u011b\u0159 potla\u010den d\u00edky mocn\u00e9 vrstv\u011b st\u00edn\u00edc\u00ed vody mezi detektorem a\u00a0dnem, stejn\u011b jako p\u0159\u00edsp\u011bvek kosmick\u00e9ho z\u00e1\u0159en\u00ed d\u00edky mocn\u00e9 vrstv\u011b vody mezi detektorem a\u00a0mo\u0159skou hladinou. Ten je nav\u00edc vlivem stabiln\u00ed hloubky prakticky konstantn\u00ed. P\u0159i m\u011b\u0159en\u00ed aktivity gama ponorn\u00fdm detektorem v\u00a0\u0159\u00ed\u010dn\u00edm prost\u0159ed\u00ed p\u0159\u00edsp\u011bvek od terestri\u00e1ln\u00ed i\u00a0kosmogenn\u00ed slo\u017eky pozad\u00ed zna\u010dn\u011b kol\u00eds\u00e1, a\u00a0t\u00edm sni\u017euje citlivost detektoru. V\u00a0\u0159\u00ed\u010dn\u00edm prost\u0159ed\u00ed je nav\u00edc pozad\u00ed ovlivn\u011bno dal\u0161\u00edm ru\u0161iv\u00fdm faktorem, a\u00a0to je aktivita radonu a\u00a0jeho p\u0159em\u011bnov\u00fdch produkt\u016f. Ty jsou p\u0159i de\u0161t\u00edch strh\u00e1v\u00e1ny z\u00a0ovzdu\u0161\u00ed a\u00a0splachov\u00e1ny z\u00a0b\u0159eh\u016f a\u00a0za ur\u010dit\u00fdch okolnost\u00ed mohou v\u00e9st a\u017e ke zdvojn\u00e1soben\u00ed celkov\u00e9 \u010detnosti impuls\u016f. N\u011bkter\u00e9 dce\u0159in\u00e9 produkty 222<\/sup>Rn, nap\u0159\u00edklad 218<\/sup>Bi zp\u016fsobuj\u00ed spektr\u00e1ln\u00ed interference s\u00a0137<\/sup>Cs, v\u00a0obdob\u00edch po siln\u00fdch de\u0161t\u00edch je tedy citlivost detek\u010dn\u00edho syst\u00e9mu vyu\u017e\u00edvaj\u00edc\u00edho ponorn\u00fd detektor siln\u011b sn\u00ed\u017eena [19, 20]. S\u00a0touto komplikac\u00ed se pot\u00fdkaj\u00ed i\u00a0pr\u016fto\u010dn\u00e9 st\u00edn\u011bn\u00e9 p\u0159\u00edstroje ur\u010den\u00e9 ke stanoven\u00ed gama aktivity \u0159\u00ed\u010dn\u00edch vod [18].<\/p>\n Vzhledem k\u00a0tomu, \u017ee vyv\u00edjen\u00fd monitorovac\u00ed syst\u00e9m SCOMO je ur\u010den p\u0159edev\u0161\u00edm pro havarijn\u00ed monitorov\u00e1n\u00ed, je pot\u0159eba, aby detek\u010dn\u00ed dovednosti SAGMA spl\u0148ovaly po\u017eadavky vyhl\u00e1\u0161ky \u010d. 360\/2016 Sb. na havarijn\u00ed monitorov\u00e1n\u00ed, ty jsou definov\u00e1ny pro 131<\/sup>I a\u00a0137<\/sup>Cs a\u00a0jejich p\u0159ehled je uveden v\u00a0tabulce 1<\/em> spole\u010dn\u011b s\u00a0po\u017eadavky na detek\u010dn\u00ed meze pro norm\u00e1ln\u00ed monitorov\u00e1n\u00ed [6].<\/p>\n Nejp\u0159\u00edsn\u011bj\u0161\u00ed legislativn\u00ed po\u017eadavek na meze detekce pro stanoven\u00ed 137<\/sup>Cs [6] v\u00a0povrchov\u00fdch vod\u00e1ch v\u00a0r\u00e1mci havarijn\u00edho monitorov\u00e1n\u00ed je 5 Bq.L-1<\/sup> (viz tabulku\u00a01<\/em>). Zohledn\u00edme-li n\u00e1sledky historicky jedin\u00e9 hav\u00e1rie jadern\u00e9 elektr\u00e1rny s\u00a0\u00fanikem invent\u00e1\u0159e reaktoru v\u00a0Evrop\u011b, tedy hav\u00e1rii jadern\u00e9 elektr\u00e1rny v\u00a0\u010cernobylu, po n\u00ed\u017e byly v\u00a0povrchov\u00fdch vod\u00e1ch z\u00e1padn\u00ed Evropy aktivity 137<\/sup>Cs a\u017e 1 Bq.L-1<\/sup>, lze konstatovat, \u017ee po\u017eadavek vyhl\u00e1\u0161ky je stanoven racion\u00e1ln\u011b a\u00a0\u017ee havarijn\u00ed monitorov\u00e1n\u00ed s\u00a0p\u0159edepsanou citlivost\u00ed by v\u00a0p\u0159\u00edpad\u011b hav\u00e1rie podobn\u00e9ho rozsahu umo\u017enilo monitorovat distribuci kontaminace ve vzd\u00e1lenosti a\u017e prvn\u00edch n\u011bkolika tis\u00edc\u016f kilometr\u016f.<\/p>\n P\u0159i v\u00fdb\u011bru konstruk\u010dn\u00ed koncepce SAGMA a\u00a0p\u0159i zohledn\u011bn\u00ed po\u017eadavk\u016f na detek\u010dn\u00ed citlivost, autonomnost a\u00a0na automatick\u00fd provoz, bylo p\u0159istoupeno ke konstrukci monitorovac\u00ed stanice na b\u00e1zi ponorn\u00e9 sondy. Jedin\u011b tato konstruk\u010dn\u00ed varianta umo\u017e\u0148uje provozovat p\u0159\u00edstroj v\u00a0re\u017eimu autonomn\u00edho energetick\u00e9ho nap\u00e1jen\u00ed pomoc\u00ed sol\u00e1rn\u00edho panelu a\u00a0dlouhodob\u00fd bezobslu\u017en\u00fd provoz za\u0159\u00edzen\u00ed. Dal\u0161\u00ed v\u00fdhodou t\u00e9to varianty jsou mimo\u0159\u00e1dn\u011b n\u00edzk\u00e9 n\u00e1klady na v\u00fdrobu monitorovac\u00ed stanice. Nev\u00fdhodou t\u00e9to konstrukce je nutnost vyrovnat se s\u00a0v\u00fdkyvy pozad\u00ed, kter\u00e9 m\u011b\u0159en\u00ed nest\u00edn\u011bnou ponornou sondou p\u0159in\u00e1\u0161\u00ed.<\/p>\n V\u00fdb\u011br detektoru byl uskute\u010dn\u011bn na z\u00e1klad\u011b porovn\u00e1n\u00ed detek\u010dn\u00edch dovednost\u00ed dvojpalcov\u00e9ho NaI(Tl), 1,5palcov\u00e9ho LaBr3<\/sub> a\u00a0t\u0159\u00edpalcov\u00e9ho NaI(Tl). Tyto varianty byly uva\u017eov\u00e1ny pro svoji cenovou dostupnost a\u00a0n\u00edzkou energetickou n\u00e1ro\u010dnost. Pou\u017eit\u00ed polovodi\u010dov\u00fdch detektor\u016f nebylo uva\u017eov\u00e1no pr\u00e1v\u011b pro vysokou energetickou n\u00e1ro\u010dnost souvisej\u00edc\u00ed s\u00a0nutnost\u00ed detektor dochlazovat. V\u00a0laboratorn\u00edch podm\u00ednk\u00e1ch sudu o\u00a0objemu 1 m3<\/sup> ve tvaru krychle napln\u011bn\u00e9m roztokem 137<\/sup>Cs s\u00a0definovanou aktivitou byly provedeny orienta\u010dn\u00ed energetick\u00e1 a\u00a0\u00fa\u010dinnost\u00ed kalibrace\u00a0porovn\u00e1van\u00fdch detektor\u016f.<\/p>\n Jako nejv\u00fdhodn\u011bj\u0161\u00ed varianta detektoru byl vyhodnocen t\u0159\u00edpalcov\u00fd NaI(Tl) s\u00a0nejvy\u0161\u0161\u00ed \u00fa\u010dinnost\u00ed detekce. Nejlep\u0161\u00ed energetick\u00e9 rozli\u0161en\u00ed prok\u00e1zal 1,5palcov\u00fd LaBr3<\/sub>, ale vzhledem k\u00a0tomu, \u017ee nen\u00ed dostupn\u00fd v\u00a0rozm\u011brech nad 1,5 palce, byl z\u00a0v\u00fdb\u011bru vy\u0159azen. Nelze v\u0161ak vylou\u010dit, \u017ee budoucnost p\u0159inese lep\u0161\u00ed zvl\u00e1dnut\u00ed technologie p\u011bstov\u00e1n\u00ed LaBr3<\/sub> krystal\u016f a\u00a0s\u00a0n\u00ed i\u00a0jejich \u0161irok\u00e9 uplatn\u011bn\u00ed na poli n\u00edzkon\u00e1kladov\u00e9 gama spektrometrie.<\/p>\n Vlastn\u00ed konstrukce za\u0159\u00edzen\u00ed SAGMA sest\u00e1v\u00e1 z\u00a0ponorn\u00e9 sondy a\u00a0z\u00a0vn\u011bj\u0161\u00ed \u0159\u00edd\u00edc\u00ed jednotky vybaven\u00e9 zdrojem elektrick\u00e9ho nap\u00e1jen\u00ed a\u00a0syst\u00e9mem p\u0159enosu dat. Ponorn\u00e1 \u010d\u00e1st je tvo\u0159ena NaI(Tl) detektorem v\u00e1lcov\u00e9ho tvaru o\u00a0pr\u016fm\u011bru 3 palce a\u00a0d\u00e9lce 3 palce zapouzd\u0159en\u00fdm ve vodot\u011bsn\u00e9m\u00a0plastov\u00e9m tubusu spolu s\u00a0foton\u00e1sobi\u010dem (SBG.D3 od NuviaTech Instruments), kter\u00fd je p\u0159ipojen k\u00a0multikan\u00e1lov\u00e9mu analyz\u00e1toru s\u00a0nastaviteln\u00fdm zes\u00edlen\u00edm v\u00a0rozsahu 256 a\u017e 2048 kan\u00e1l\u016f (NuNA MCB3 od NuviaTech Instruments).<\/p>\n Popsan\u00fd gamaspektrometrick\u00fd syst\u00e9m je schopen detekovat energie foton\u016f v\u00a0rozsahu 50 a\u017e 1900 keV, do kter\u00e9ho spad\u00e1 v\u011bt\u0161ina gama emituj\u00edc\u00edch radionuklid\u016f. Energetick\u00e9 rozli\u0161en\u00ed na energii 137<\/sup>C 661 keV je 7,5 %. Celkov\u00e1 hmotnost syst\u00e9mu je asi 10 kilogram\u016f.<\/p>\n P\u0159enos dat z\u00a0multikan\u00e1lov\u00e9ho analyz\u00e1toru do \u0159\u00edd\u00edc\u00ed jednotky je uskute\u010d\u0148ov\u00e1n pomoc\u00ed p\u0159ipojen\u00ed typu Ethernet. \u0158\u00edd\u00edc\u00ed jednotka sest\u00e1v\u00e1 z\u00a0po\u010d\u00edta\u010de vybaven\u00e9ho komer\u010dn\u00edm SW Gamwin 2019 na zpracov\u00e1n\u00ed gamaspektrometrick\u00e9ho sign\u00e1lu a\u00a0z\u00a0komunika\u010dn\u00edho modulu, kter\u00fd umo\u017e\u0148uje odes\u00edl\u00e1n\u00ed dat p\u0159es GPRS nebo p\u0159es satelitn\u00ed telefon. Nap\u00e1jen\u00ed sol\u00e1rn\u00edm panelem, p\u0159\u00edpadn\u011b kombinac\u00ed sol\u00e1rn\u00edho panelu a\u00a0v\u011btrn\u00e9 turb\u00edny je sdru\u017eeno s\u00a0lithiovou bateri\u00ed o\u00a0kapacit\u011b 900 Ah schopnou zajistit provoz SAGMA po dobu 14 dn\u016f. Syst\u00e9m SAGMA instalovan\u00fd v\u00a0ter\u00e9nn\u00edch podm\u00ednk\u00e1ch a\u00a0pou\u017eit\u00e1 ponorn\u00e1 sonda jsou zobrazeny na obr.\u00a01.<\/em><\/p>\n Vzhledem k tomu, \u017ee vlivem zm\u011bn teploty doch\u00e1z\u00ed k posun\u016fm energetick\u00e9 kalibrace, SW Gamwin prov\u00e1d\u00ed periodickou stabilizaci spektra zalo\u017eenou na m\u011b\u0159en\u00ed v\u0161udyp\u0159\u00edtomn\u00e9ho 40<\/sup>K s\u00a0energi\u00ed 1461 keV.<\/p>\n Precizn\u00ed energetick\u00e1 a\u00a0\u00fa\u010dinnostn\u00ed kalibrace byla provedena pomoc\u00ed etalonov\u00fdch roztok\u016f 241<\/sup>Am, 131<\/sup>I, 134<\/sup>Cs, 137<\/sup>Cs a\u00a060<\/sup>Co o\u00a0aktivit\u011b p\u0159ibli\u017en\u011b 10 kBq.m-3<\/sup> v\u00a0plastov\u00e9m sudu tvaru krychle o\u00a0rozm\u011brech 1\u00a0\u00d7 1\u00a0\u00d7 1 m. Etalonov\u00e9 roztoky byly stabilizov\u00e1ny proti nehomogenit\u011b a\u00a0proti sorpci na st\u011bnu p\u0159\u00eddavkem stabiln\u00edch nosi\u010d\u016f a\u00a0miner\u00e1ln\u00edch kyselin.<\/p>\n Vlastn\u00ed kalibrace detektoru byla provedena prom\u011b\u0159ov\u00e1n\u00edm kalibra\u010dn\u00edch roztok\u016f po dobu 48 hodin v\u00a0sekven\u010dn\u00edm detek\u010dn\u00edm re\u017eimu s\u00a0pou\u017eit\u00edm 10minutov\u00e9 sekvence. Prost\u0159ednictv\u00edm sekven\u010dn\u00edho m\u011b\u0159en\u00ed bylo ov\u011b\u0159eno, \u017ee aktivita kalibra\u010dn\u00edch roztok\u016f se b\u011bhem kalibrace nem\u011bn\u00ed, tedy \u017ee kalibra\u010dn\u00ed roztok je homogenn\u00ed.<\/p>\n P\u0159epo\u010det \u00fa\u010dinnostn\u00ed kalibrace z\u00a0geometrie barelu o\u00a0rozm\u011brech 1\u00a0\u00d7 1\u00a0\u00d7 1 m na nekone\u010dnou 4\u03c0 geometrii byl proveden simulac\u00ed v\u00a0prost\u0159ed\u00ed Monte Carlo. Hodnota korek\u010dn\u00edho koeficientu pro vysok\u00e9 energie gama (60<\/sup>Co) je 85 %. To znamen\u00e1, \u017ee v\u00a0nekone\u010dn\u00e9 4\u03c0 geometrii v\u00a0\u0159\u00ed\u010dn\u00ed vod\u011b poch\u00e1z\u00ed 85 % detekovan\u00fdch foton\u016f z\u00a0prostoru virtu\u00e1ln\u00ed krychle o\u00a0rozm\u011brech 1\u00a0\u00d7 1\u00a0\u00d7 1 m, v\u00a0jej\u00edm\u017e st\u0159edu je detektor.<\/p>\n K\u00a0prov\u011b\u0159en\u00ed detek\u010dn\u00edch dovednost\u00ed SAGMA ve vodn\u00edch toc\u00edch bylo provedeno dlouhodob\u00e9 m\u011b\u0159en\u00ed \u0159\u00ed\u010dn\u00ed vody v\u00a0t\u00e1rovac\u00edm kan\u00e1le V\u00fdzkumn\u00e9ho \u00fastavu vodohospod\u00e1\u0159sk\u00e9ho T. G. Masaryka, v. v. i., (V\u00daV TGM) v\u00a0Praze pomoc\u00ed ponorn\u00e9 \u010d\u00e1sti SAGMA. Prakticky \u0161lo o\u00a0m\u011b\u0159en\u00ed odezvy sondy na poza\u010fov\u00e9 koncentrace radionuklid\u016f v\u00a0\u0159\u00ed\u010dn\u00ed vod\u011b. Testov\u00e1n\u00ed bylo prov\u00e1d\u011bno v\u00a0poloter\u00e9nn\u00edch podm\u00ednk\u00e1ch, proto\u017ee neprob\u00edhalo ve standardn\u00edm \u0159e\u010di\u0161ti s\u00a0prom\u011bnlivou \u00farovn\u00ed vodn\u00ed hladiny a\u00a0s\u00a0bahnit\u00fdm dnem, ale v\u00a0kan\u00e1le s\u00a0betonov\u00fdm dnem a\u00a0s\u00a0\u00farovn\u00ed hladiny regulovanou p\u0159epadem. Nicm\u00e9n\u011b slo\u017een\u00ed vody v\u00a0kan\u00e1le kol\u00eds\u00e1 stejn\u011b jako v\u00a0\u0159ece Vltav\u011b. Hloubka vody v\u00a0t\u00e1rovac\u00edm kan\u00e1le je stabilizov\u00e1na na 1,8 m, ponorn\u00e1 \u010d\u00e1st sondy byla do vody zano\u0159ena tak, aby se st\u0159ed detektoru nach\u00e1zel 0,8 m ode dna a\u00a01 m od vodn\u00ed hladiny. Sb\u011br pozad\u00ed byl uskute\u010dn\u011bn v\u00a0obdob\u00ed od dubna 2017 do \u010dervna 2019, kdy byly zkompletov\u00e1ny prvn\u00ed t\u0159i exempl\u00e1\u0159e SAGMA a\u00a0mohlo b\u00fdt p\u0159istoupeno k\u00a0zah\u00e1jen\u00ed\u00a0testov\u00e1n\u00ed syst\u00e9mu v\u00a0ter\u00e9nn\u00edch (autentick\u00fdch \u0159\u00ed\u010dn\u00edch) podm\u00ednk\u00e1ch.<\/p>\n Vyhodnocen\u00ed datasetu z\u00edskan\u00e9ho dlouhodob\u00fdm m\u011b\u0159en\u00edm v\u00a0t\u00e1rovac\u00edm kan\u00e1le bylo jedn\u00edm z\u00a0kl\u00ed\u010dov\u00fdch krok\u016f cel\u00e9ho procesu v\u00fdvoje SAGMA. Spektra byla z\u00edsk\u00e1na kontinu\u00e1ln\u00edm m\u011b\u0159en\u00edm v\u00a0desetiminutov\u00e9m integra\u010dn\u00edm okn\u011b. P\u0159i tomto m\u011b\u0159ic\u00edm re\u017eimu SW kontinu\u00e1ln\u011b vyhodnocuje spektrum tvo\u0159en\u00e9 pulsy detekovateln\u00fdmi za posledn\u00edch 10 minut. Vyhodnocen\u00edm spektra je tedy z\u00edsk\u00e1na informace o\u00a0pr\u016fm\u011brn\u00e9m slo\u017een\u00ed vody, kter\u00e1 protekla kolem detektoru za posledn\u00edch 10 minut. Integra\u010dn\u00ed dobu je mo\u017en\u00e9 libovoln\u011b m\u011bnit, krat\u0161\u00ed integra\u010dn\u00ed doba vede ke sn\u00ed\u017een\u00ed citlivosti, del\u0161\u00ed zase ke sn\u00ed\u017een\u00ed reprezentativnosti. Aby bylo mo\u017en\u00e9 spektra analyzovat i\u00a0zp\u011btn\u011b, byly ka\u017ed\u00fdch 10 minut n\u00e1po\u010dty za posledn\u00edch 10 minut ukl\u00e1d\u00e1ny.<\/p>\n \u010casov\u00fd pr\u016fb\u011bh gama spekter vykazuje stabiln\u00ed koncentrace gama aktivity v\u00a0\u0159ece Vltav\u011b, k\u00a0v\u00fdrazn\u00e9mu nav\u00fd\u0161en\u00ed doch\u00e1z\u00ed pouze po de\u0161t\u00edch. Po bou\u0159\u00edch a\u00a0po p\u0159\u00edvalov\u00fdch de\u0161t\u00edch doch\u00e1z\u00ed v\u00a0\u0159\u00ed\u010dn\u00ed vod\u011b a\u017e ke zdvojn\u00e1soben\u00ed celkov\u00e9 aktivity gama. To je zp\u016fsobeno splachov\u00e1n\u00edm radonu a\u00a0jeho p\u0159em\u011bnov\u00fdch produkt\u016f jednak p\u0159\u00edmo ze vzduchu, jednak z\u00a0povrchu \u0159\u00ed\u010dn\u00edch b\u0159eh\u016f. Jak je patrn\u00e9 z\u00a0obr. \u00a02<\/em>, v\u00a0de\u0161\u0165ov\u00e9m spektru je v\u00fdrazn\u011b nav\u00fd\u0161ena p\u0159edev\u0161\u00edm aktivita 214<\/sup>Bi s\u00a0energi\u00ed 609\u00a0keV, d\u00e1le pak 214<\/sup>Pb (242, 295 a\u00a0352 keV).<\/p>\n Standardn\u00ed metoda anal\u00fdzy je zalo\u017eena na p\u00edkov\u00e9 anal\u00fdze s\u00a0vyu\u017eit\u00edm numerick\u00e9 derivace spektra, kter\u00e1 zohled\u0148uje pouze lok\u00e1ln\u00ed vlastnosti spektra a\u00a0pro slo\u017eit\u00e1 spektra s\u00a0v\u00fdskytem interferuj\u00edc\u00edch radionuklid\u016f je ne\u00fa\u010dinn\u00e1. P\u0159i pou\u017eit\u00ed standardn\u00ed anal\u00fdzy gama spektra ovlivn\u011bn\u00e9ho de\u0161\u0165ovou ud\u00e1lost\u00ed doch\u00e1z\u00ed ke zv\u00fd\u0161en\u00ed hodnot detek\u010dn\u00edch mez\u00ed pro jednotliv\u00e9 radionuklidy, zejm\u00e9na pro ty, u\u00a0nich\u017e doch\u00e1z\u00ed ke spektr\u00e1ln\u00edm interferenc\u00edm. Siln\u011b ovlivn\u011bny jsou tak\u00e9 detek\u010dn\u00ed meze pro 137<\/sup>Cs, jeho\u017e hlavn\u00ed energie gama je 662 keV p\u0159i energetick\u00e9m rozli\u0161en\u00ed NaI(Tl) detektoru koliduje pr\u00e1v\u011b s\u00a0energi\u00ed 214<\/sup>Bi 609 keV a\u00a0pro 131<\/sup>I s\u00a0hlavn\u00ed energi\u00ed gama 364 keV, se kter\u00fdm zase koliduje p\u00edk 214<\/sup>Pb s\u00a0energi\u00ed 352 keV.<\/p>\n Z\u00a0d\u016fvodu prom\u011bnlivosti pozad\u00ed a\u00a0spektr\u00e1ln\u00edch interferenc\u00ed byla jako prim\u00e1rn\u00ed anal\u00fdza zvolena metoda PCR (Principle Component Regression), kter\u00e1 pat\u0159\u00ed do rodiny dekonvolu\u010dn\u00edch algoritm\u016f. Jej\u00ed v\u00fdhodou je zejm\u00e9na to, \u017ee b\u00e1zov\u00e1 spektra lze odvodit na z\u00e1klad\u011b souboru poza\u010fov\u00fdch m\u011b\u0159en\u00ed. Jednotliv\u00e1 poza\u010fov\u00e1 spektra jsou pak uspo\u0159\u00e1d\u00e1na do matice, jej\u00ed\u017e singul\u00e1rn\u00ed rozklad (NASVD\u00a0\u2013 Noise Adjusted Component Regression) poskytuje b\u00e1zov\u00e1 spektra, kter\u00e1 lze pou\u017e\u00edt pro p\u0159esn\u00e9 fitov\u00e1n\u00ed pozad\u00ed metodou nejmen\u0161\u00edch \u010dtverc\u016f. Dopln\u011bn\u00edm b\u00e1zov\u00e9ho souboru o\u00a0spektr\u00e1ln\u00ed odezvu detektoru pro vybran\u00e9 radionuklidy lze pak nejenom detekovat, ale i\u00a0kvantifikovat aktivitu t\u011bchto radionuklid\u016f.<\/p>\n Tato metoda je pou\u017e\u00edv\u00e1na v\u00a0oblasti leteck\u00e9 gama spektrometrie [21], m\u016f\u017ee ale b\u00fdt pou\u017eita i\u00a0v\u00a0jin\u00fdch oblastech, v\u00a0pom\u011brech \u010cR ji\u017e byla vyu\u017eita p\u0159i kontinu\u00e1ln\u00edm m\u011b\u0159en\u00ed gama aktivity v\u00a0aerosolech pomoc\u00ed NaI(Tl) detektoru [7].<\/p>\n Stanoven\u00ed mez\u00ed detekce pro spektra analyzovan\u00e1 metodou NASVD bylo provedeno Monte Carlo simulac\u00ed, ve kter\u00e9 byly do poza\u010fov\u00fdch spekter um\u011ble p\u0159id\u00e1v\u00e1ny impulsy odpov\u00eddaj\u00edc\u00ed jist\u00e9 virtu\u00e1ln\u00ed aktivit\u011b hodnocen\u00e9ho radionuklidu. Tato spektra pak byla podrobena anal\u00fdze detek\u010dn\u00edm algoritmem. V\u00fdsledek anal\u00fdzy (regresn\u00ed koeficient) byl n\u00e1sledn\u011b vzta\u017een k\u00a0virtu\u00e1ln\u00ed aktivit\u011b (aktivit\u011b odpov\u00eddaj\u00edc\u00ed um\u011ble p\u0159idan\u00fdm puls\u016fm).<\/p>\n V\u00fdpo\u010det nejmen\u0161\u00ed detekovateln\u00e9 aktivity (NDA) je vyj\u00e1d\u0159en na\u00a0obr. 3<\/em>. P\u0159idan\u00e1 aktivita odpov\u00edd\u00e1 NDA, kdy\u017e pod\u00edl fale\u0161n\u011b negativn\u00edch a\u00a0fale\u0161n\u011b pozitivn\u00edch pozorov\u00e1n\u00ed je pr\u00e1v\u011b 5 %. V\u00a0grafick\u00e9m zn\u00e1zorn\u011bn\u00ed je to aktivita odpov\u00eddaj\u00edc\u00ed pr\u016fse\u010d\u00edku p\u0159\u00edmky odpov\u00eddaj\u00edc\u00ed 95% toleran\u010dn\u00edmu intervalu hodnot regresn\u00edho koeficientu pro spektra bez p\u0159idan\u00e9 aktivity a\u00a0p\u0159\u00edmky odpov\u00eddaj\u00edc\u00ed jednostrann\u00e9mu predik\u010dn\u00edmu intervalu kalibra\u010dn\u00ed k\u0159ivky s\u00a0pokryt\u00edm 95 %.<\/p>\n \u00da\u010dinnost algoritmu NASVD p\u0159i ode\u010dtu pozad\u00ed lze dob\u0159e demonstrovat porovn\u00e1n\u00edm um\u011ble kontaminovan\u00fdch gama spekter na \u00farovni NDA pro NASVD a\u00a0pro standardn\u00ed metodu ode\u010dtu pozad\u00ed. Jako standardn\u00ed metoda byl pou\u017eit v\u00fdpo\u010det SW Gamwin pracuj\u00edc\u00ed se standardn\u00edm p\u0159\u00edstupem podle L. A. Currieho [22]. Na obr. 4<\/em> je zobrazeno poza\u010fov\u00e9 spektrum v\u00a0oblasti z\u00e1jmu pro 137<\/sup>Cs (vymezeno b\u00edlou barvou). Tmav\u011b mod\u0159e vybarven\u00e1 oblast vymezuje um\u011ble injektovan\u00e9 pulsy 137<\/sup>Cs pot\u0159ebn\u00e9 k\u00a0dosa\u017een\u00ed NDA p\u0159i vyhodnocen\u00ed pomoc\u00ed metody NASVD, sv\u011btle mod\u0159e vybarven\u00e1 oblast pak pulsy pot\u0159ebn\u00e9 k\u00a0dosa\u017een\u00ed NDA p\u0159i standardn\u00ed metod\u011b.<\/p>\n Vzhledem k\u00a0tomu, \u017ee za ur\u010dit\u00fdch okolnost\u00ed m\u016f\u017ee b\u00fdt \u00fa\u010deln\u00e9 prov\u00e1d\u011bt kontinu\u00e1ln\u00ed m\u011b\u0159en\u00ed v\u00a0del\u0161\u00edch integra\u010dn\u00edch \u010dasech, bylo s\u010d\u00edt\u00e1n\u00edm p\u016fvodn\u00edch 10\u00a0m spekter vytvo\u0159eno p\u011bt dataset\u016f obsahuj\u00edc\u00ed 10m, 1h, 4h, 12h a\u00a024h spektra. Vzhledem k\u00a0tomu, \u017ee spektra z\u00edskan\u00e1 po de\u0161\u0165ov\u00fdch ud\u00e1lostech vykazuj\u00ed v\u00fdrazn\u00e9 fluktuace, byly vytvo\u0159eny dv\u011b skupiny spekter v\u00a0r\u00e1mci t\u011bchto p\u011bti dataset\u016f, 1.\u00a0spektra zm\u011b\u0159en\u00e1 b\u011bhem a\u00a0po de\u0161\u0165ov\u00fdch ud\u00e1lostech, d\u00e1le jen \u201ede\u0161\u0165ov\u00e1 spektra\u201c a\u00a02. spektra ovlivn\u011bn\u00e1 i\u00a0neovlivn\u011bn\u00e1 de\u0161\u0165ov\u00fdmi ud\u00e1lostmi, d\u00e1le jen \u201ev\u0161echna spektra\u201c. Rozd\u011blen\u00ed spekter umo\u017enilo prov\u00e9st zhodnocen\u00ed vlivu nep\u0159\u00edzniv\u00fdch meteorologick\u00fdch podm\u00ednek na NDA.<\/p>\n Pro v\u0161ech deset dataset\u016f pak byly stanoveny hodnoty NDA pro 137<\/sup>Cs a\u00a0131<\/sup>I, a\u00a0to jednak standardn\u00ed metodou ode\u010dtu pozad\u00ed, jednak pomoc\u00ed metody NASVD. Porovn\u00e1n\u00ed je zobrazeno v\u00a0tabulk\u00e1ch 2<\/em> a\u00a03<\/em>.<\/p>\n Porovn\u00e1n\u00ed standardn\u00ed metody ode\u010dtu pozad\u00ed a\u00a0NASVD metody ukazuje, \u017ee \u010d\u00edm jsou podm\u00ednky m\u011b\u0159en\u00ed m\u00e9n\u011b p\u0159\u00edzniv\u00e9 (v\u011bt\u0161\u00ed v\u00fdkyvy pozad\u00ed, krat\u0161\u00ed integra\u010dn\u00ed \u010das), t\u00edm m\u00e1 zapojen\u00ed NASVD v\u011bt\u0161\u00ed v\u00fdznam. Nejv\u011bt\u0161\u00ed rozd\u00edl ve v\u00fdsledn\u00fdch NDA byl zaznamen\u00e1n p\u0159i pou\u017eit\u00ed krat\u0161\u00edch integra\u010dn\u00edch \u010das\u016f u\u00a0de\u0161\u0165ov\u00fdch spekter. V\u00a0takov\u00fdch p\u0159\u00edpadech vede pou\u017eit\u00ed NASVD a\u017e k\u00a0p\u011btin\u00e1sobn\u00e9mu sn\u00ed\u017een\u00ed v\u00fdsledn\u00e9 NDA, zat\u00edmco p\u0159i stabiln\u00edm pozad\u00ed a\u00a0dlouh\u00fdch integra\u010dn\u00edch \u010dasech mohou b\u00fdt v\u00fdsledky obou metod srovnateln\u00e9.<\/p>\n Hodnoty dosa\u017een\u00fdch NVA mohou m\u00edt velk\u00fd vliv na praktickou uplatnitelnost syst\u00e9mu v\u00a0havarijn\u00ed p\u0159ipravenosti st\u00e1tu. Porovn\u00e1n\u00edm hodnot NDA v\u00a0tabulk\u00e1ch 2<\/em> a\u00a03<\/em> s\u00a0po\u017eadavky [6] vypl\u00fdv\u00e1, \u017ee p\u0159i desetiminutov\u00e9 integra\u010dn\u00ed dob\u011b by za de\u0161\u0165ov\u00e9 ud\u00e1losti SAGMA se standardn\u00ed metodou ode\u010dtu pozad\u00ed legislativn\u00ed po\u017eadavky nesplnila, zat\u00edmco p\u0159i pou\u017eit\u00ed metody NASVD ano.<\/p>\n Metoda NASVD d\u00e1le p\u0159in\u00e1\u0161\u00ed zv\u00fdhodn\u011bn\u00ed SAGMA ve srovn\u00e1n\u00ed s\u00a0konkurenc\u00ed. Ve srovn\u00e1n\u00ed se SARA Water System, p\u0159\u00edstrojem podobn\u00e9 konstrukce [19] vykazuje SAGMA polovi\u010dn\u00ed hodnoty detek\u010dn\u00edch mez\u00ed. Ve srovn\u00e1n\u00ed s\u00a0p\u0159\u00edstrojem m\u011b\u0159\u00edc\u00edm vodu ve st\u00edn\u011bn\u00e9 pr\u016fto\u010dn\u00e9 n\u00e1dob\u011b [18] byly p\u0159i 24hodinov\u00e9m integra\u010dn\u00edm \u010dase a\u00a0pou\u017eit\u00ed datasetu \u201ev\u0161echna spektra\u201c meze detekce za\u0159\u00edzen\u00ed SAGMA p\u0159ibli\u017en\u011b 15\u00d7 vy\u0161\u0161\u00ed. To je zp\u016fsobeno skute\u010dnost\u00ed, \u017ee p\u0159i m\u011b\u0159en\u00ed ponornou sondou nejsou odst\u00edn\u011bny dominantn\u00ed slo\u017eky pozad\u00ed (terestri\u00e1ln\u00ed, kosmick\u00e9) tak \u00fa\u010dinn\u011b, jako p\u0159i pou\u017eit\u00ed olov\u011bn\u00e9ho st\u00edn\u011bn\u00ed. Ov\u0161em p\u0159i zkr\u00e1cen\u00ed integra\u010dn\u00edho \u010dasu na 10\u00a0minut ji\u017e je dominantn\u00ed \u010d\u00e1st pozad\u00ed tvo\u0159ena radionuklidy obsa\u017een\u00fdmi v\u00a0prom\u011b\u0159ovan\u00e9 vod\u011b. D\u00edky \u00fa\u010dinn\u00e9mu ode\u010dtu tohoto zdroje fluktuac\u00ed metodou NASVD je dosa\u017eeno sn\u00ed\u017een\u00ed pom\u011bru mezi hodnotami NDA za\u0159\u00edzen\u00ed SAGMY a\u00a0pr\u016fto\u010dn\u00e9 st\u00edn\u011bn\u00e9 sondy na hodnotu 1,4.<\/p>\n Vzhledem k\u00a0tomu, \u017ee SAGMA je ur\u010dena p\u0159ednostn\u011b pro havarijn\u00ed monitorov\u00e1n\u00ed, m\u016f\u017eeme desetiminutov\u00fd integra\u010dn\u00ed \u010das pova\u017eovat za p\u0159ednostn\u00ed re\u017eim p\u0159edpokl\u00e1dan\u00e9ho vyu\u017eit\u00ed vyv\u00edjen\u00e9ho syst\u00e9mu (v\u00fdhoda spo\u010d\u00edvaj\u00edc\u00ed ve vysok\u00e9m \u010dasov\u00e9m rozli\u0161en\u00ed stanoven\u00e9 aktivity). Za podm\u00ednek havarijn\u00edho monitorov\u00e1n\u00ed je oproti konkurenci SAGMA zv\u00fdhodn\u011bna zejm\u00e9na jednoduchou robustn\u00ed konstrukc\u00ed schopnou bez p\u0159eru\u0161en\u00ed m\u011b\u0159en\u00ed zvl\u00e1dnout n\u00e1sledky havarijn\u00ed situace.<\/p>\n A\u010dkoli oproti st\u00edn\u011bn\u00fdm syst\u00e9m\u016fm vykazuje SAGMA v\u00fdznamn\u011b ni\u017e\u0161\u00ed citlivost, p\u0159i pou\u017eit\u00ed poza\u010fov\u00e9ho datasetu \u201ev\u0161echna spektra\u201c dosahuje SAGMA p\u0159i p\u0159ibli\u017en\u011b 24hodinov\u00e9m integra\u010dn\u00edm \u010dase NDA pro 137<\/sup>Cs hodnoty 0,1 Bq.L-1<\/sup>, tedy legislativn\u00edho po\u017eadavku pro norm\u00e1ln\u00ed monitorov\u00e1n\u00ed [6]. V\u00fd\u0161e uveden\u00e9 hodnoty mez\u00ed detekce spo\u010d\u00edtan\u00e9 z\u00a0poza\u010fov\u00fdch hodnot vody v\u00a0t\u00e1rovac\u00edm kan\u00e1le ve V\u00daV TGM nazna\u010duj\u00ed, \u017ee SAGMA m\u00e1 d\u00edky metod\u011b NASVD z\u00a0hlediska detek\u010dn\u00ed citlivosti potenci\u00e1l zcela nahradit sou\u010dasn\u00fd zp\u016fsob monitorov\u00e1n\u00ed gama aktivity v\u00a0povrchov\u00fdch vod\u00e1ch.<\/p>\n B\u011bhem l\u00e9ta 2019 byly zkompletov\u00e1ny prvn\u00ed t\u0159i exempl\u00e1\u0159e p\u0159\u00edstroje SAGMA v\u010detn\u011b autonomn\u00edho z\u00e1sobov\u00e1n\u00ed elektrickou energi\u00ed a\u00a0d\u00e1lkov\u00e9ho p\u0159enosu dat. P\u0159\u00edstroje byly um\u00edst\u011bny do monitorovac\u00edch bod\u016f, \u010d\u00edm\u017e byla sestavena prvotn\u00ed forma monitorovac\u00ed s\u00edt\u011b SCOMO. Prvn\u00ed exempl\u00e1\u0159 SAGMA nahradil provizorn\u00ed sondu v\u00a0t\u00e1rovac\u00edm kan\u00e1le V\u00daV TGM, dal\u0161\u00ed dva byly um\u00edst\u011bny v\u00a0re\u00e1ln\u00fdch \u0159\u00ed\u010dn\u00edch podm\u00ednk\u00e1ch \u0159eky Jihlavy v\u00a0lokalit\u011b Ivan\u010dice (viz obr. 1<\/em>) a\u00a0\u0159eky Vltavy v\u00a0lokalit\u011b Ko\u0159ensko. Minis\u00ed\u0165 SCOMO je od srpna 2019 provozov\u00e1na ve zku\u0161ebn\u00edm provozu, kter\u00fd bude pokra\u010dovat do dubna 2020. C\u00edlem je po sko\u010den\u00ed testovac\u00edho provozu SCOMO za\u010dlenit do syst\u00e9mu monitorov\u00e1n\u00ed radia\u010dn\u00ed situace v\u00a0\u010cR.<\/p>\n Byla sestrojena monitorovac\u00ed stanice um\u011bl\u00e9 aktivity gama v\u00a0povrchov\u00fdch vod\u00e1ch na b\u00e1zi n\u00edzkorozpo\u010dtov\u00e9 ponorn\u00e9 sondy sdru\u017een\u00e9 s\u00a0\u0159\u00edd\u00edc\u00ed jednotkou a\u00a0s\u00a0autonomn\u00edm zdrojem nap\u00e1jen\u00ed. D\u00edky algoritmu NASVD byla citlivost monitorovac\u00ed stanice zv\u00fd\u0161ena natolik, \u017ee vyhovuje legislativn\u00edm po\u017eadavk\u016fm a\u00a0za mimo\u0159\u00e1dn\u011b nep\u0159\u00edzniv\u00fdch klimatick\u00fdch podm\u00ednek vyvinut\u00fd syst\u00e9m m\u016f\u017ee konkurovat i\u00a0p\u0159\u00edstroj\u016fm m\u011b\u0159\u00edc\u00edm vzorky vody ve st\u00edn\u011bn\u00e9 cele. Z\u00a0monitorovac\u00edch stanic byla sestavena monitorovac\u00ed minis\u00ed\u0165, jej\u00ed schopnost autonomn\u00edho a\u00a0automatick\u00e9ho provozu je moment\u00e1ln\u011b testov\u00e1na. V\u00a0r\u00e1mci testov\u00e1n\u00ed minis\u00edt\u011b jsou sb\u00edr\u00e1ny datasety popisuj\u00edc\u00ed fluktuace pozad\u00ed v\u00a0jednotliv\u00fdch lokalit\u00e1ch.<\/p>\n V\u00fdzkum byl podpo\u0159en projektem Ministerstva vnitra \u010cesk\u00e9 republiky (projekt VI20172020083). <\/em><\/p>\n","protected":false},"excerpt":{"rendered":" \u010cl\u00e1nek popisuje monitorovac\u00ed stanici vyvinutou pro pot\u0159eby monitorov\u00e1n\u00ed radia\u010dn\u00ed situace \u010cesk\u00e9 republiky (\u010cR) a jej\u00ed potenci\u00e1l pro \u00fa\u010dely p\u0159ipravenosti k odezv\u011b na radia\u010dn\u00ed mimo\u0159\u00e1dnou ud\u00e1lost. <\/p>\n","protected":false},"author":8,"featured_media":7201,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[91,87],"tags":[1759,1758,1757,1756,1755],"coauthors":[1739,1740,1741],"class_list":["post-7349","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-applied-ecology","category-hydrochemistry-radioecology-microbiology","tag-137cs","tag-havarijni-monitorovani","tag-monitorovani-radiacni-situace","tag-naitl","tag-spektrometrie-gama"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/7349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=7349"}],"version-history":[{"count":4,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/7349\/revisions"}],"predecessor-version":[{"id":30555,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/7349\/revisions\/30555"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/7201"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=7349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=7349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=7349"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=7349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a>\nObr. 1. Vlevo: SAGMA instalovan\u00fd v\u00a0are\u00e1lu vodn\u00ed elektr\u00e1rny Na R\u00e9n\u011b v\u00a0Ivan\u010dic\u00edch, \u0159eka Morava; vpravo: ponorn\u00e1 sonda sest\u00e1vaj\u00edc\u00ed z\u00a0detektoru (vpravo naho\u0159e) a\u00a0foton\u00e1sobi\u010de (vpravo dole)
\nFig. 1. Left: SAGMA installed in the area of hydro power plant Na R\u00e9n\u011b in Ivan\u010dice, the\u00a0Morava River; right: immersion probe consisting of detector (up) and photomultiplier (down)<\/h6>\nMonitorov\u00e1n\u00ed povrchov\u00fdch vod<\/h2>\n
Monitorovac\u00ed syst\u00e9m SAGMA a\u00a0s\u00ed\u0165 SCOMO v\u00a0kontextu havarijn\u00edho monitorov\u00e1n\u00ed<\/h2>\n
Tabulka 1. Po\u017eadavky vyhl\u00e1\u0161ky \u010d. 360\/2016 Sb. na detek\u010dn\u00ed meze pro stanoven\u00ed um\u011bl\u00e9 gama aktivity v\u00a0povrchov\u00fdch vod\u00e1ch
\nTable 1. Requirements of Decree No. 360\/2016 Coll. detection limits for the determination of artificial gamma activity in surface water<\/h5>\n<\/a>\nV\u00fdvoj stanice na kontinu\u00e1ln\u00ed monitorov\u00e1n\u00ed aktivity gama ve vod\u00e1ch a\u00a0vybudov\u00e1n\u00ed monitorovac\u00ed minis\u00edt\u011b<\/h2>\n
<\/a>\nObr. 2. Nav\u00fd\u0161en\u00ed p\u0159\u00edrodn\u00edho pozad\u00ed vlivem p\u0159\u00edsp\u011bvku radonu a\u00a0jeho p\u0159em\u011bnov\u00fdch produkt\u016f spl\u00e1chnut\u00fdch do vodn\u00edho toku de\u0161t\u011bm ve srovn\u00e1n\u00ed se spektrem mimo de\u0161\u0165ov\u00e9 obdob\u00ed
\nFig. 2. Increase of natural background due to the contribution of radon and its conversion products flushed into the watercourse by rain compared to the spectrum outside the rain season<\/h6>\nTabulka 2. Hodnoty NDA pro pozad\u00ed datasetu \u201ev\u0161echna spektra\u201d
\nTable 2. NDA values for \u201call spectrum\u201d dataset background<\/h5>\n<\/a>\nZv\u00fd\u0161en\u00ed citlivosti detek\u010dn\u00edho syst\u00e9mu SAGMA pomoc\u00ed NASVD<\/h2>\n
<\/a>\nObr. 3. Metoda stanoven\u00ed NDA p\u0159i pou\u017eit\u00ed algoritmu NASVD; k\u00a0v\u00fdpo\u010dtu byla pou\u017eita mno\u017eina 5\u00a0\u00d7\u00a0104<\/sup> spekter s\u00a0matematicky simulovan\u00fdm p\u0159\u00eddavkem 137<\/sup>Cs o\u00a0aktivit\u011b mezi 0\u00a0a\u00a0600 Bq.m3<\/sup>; pr\u016fse\u010d\u00edk p\u0159\u00edmek zna\u010d\u00edc\u00edch 95% toleran\u010dn\u00ed interval poza\u010fov\u00e9 odezvy a\u00a095% odezvy na spektra s\u00a0p\u0159idanou aktivitou indikuje NVA
\nFig. 3. Method of determination of NDA using an algorithm NASVD; a\u00a0set of 5\u00a0\u00d7\u00a0104<\/sup> spectrum with mathematically simulated addiction of 137<\/sup>Cs with activity between 0\u00a0and\u00a0600\u00a0Bq.m3<\/sup> was used for the calculation; intersection of lines indicating 95% background response interval and 95% response to spectrum with added activity indicated by NVA<\/h6>\n<\/a>\nObr. 4. Porovn\u00e1n\u00ed spekter um\u011ble kontaminovan\u00fdch pulsy 137<\/sup>Cs na \u00farovni odpov\u00eddaj\u00edc\u00ed NDA pro r\u016fzn\u00e9 metody ode\u010dtu pozad\u00ed; p\u0159i pou\u017eit\u00ed standardn\u00ed metody je hodnota NDA 0,84 Bq.L-1<\/sup>, p\u0159i pou\u017eit\u00ed NASVD metody je to 0,24 Bq.L-1
\n<\/sup>Fig. 4. The comparison of spectrum artificially with 137<\/sup>Cs pulses at the NDA-compliant level for different background subtraction methods; when using the standard method the value is NDA 0.84 Bq.L-1<\/sup>, when using NASVD method the value is 0.24 Bq.L-1<\/sup><\/h6>\nTabulka 3. Hodnoty NDA pro pozad\u00ed datasetu \u201ede\u0161\u0165ov\u00e1 spektra\u201c
\nTable 3. NDA values for the \u201crainfall spectrum\u201d dataset background<\/h5>\n<\/a>\nSestaven\u00ed minis\u00edt\u011b SCOMO<\/h2>\n
Z\u00e1v\u011br<\/h2>\n
Pod\u011bkov\u00e1n\u00ed<\/h3>\n