2019 ⦽ǎႊᔍᖒ⠱ʑྜྷ⦺⫭ ⇹ĥ⦺ᚁݡ⫭ םྙ᧞Ḳ
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Review on Revision History of ANSI/ANS-18.1 and PWR-GALE Along With Its
Potential Impact to Anticipated Radioactive Source Terms to Environment From PWRs
Ji Woo Lee, Ji Su Kang, Sae Gun Lee, and Jae Hak Cheong*
Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea
*
1. Introduction
In case of Korea, as same as US NRC, uses the PWR-GALE and the concentrations in principal fluid systems of the reference PWRs as given in ANSI / ANS-18.1 to estimate the annual release rate of Nuclear Power Plants(NPPs). After first published in 1976, ANSI / ANS-18.1 has been revised in 1984, 1999 and 2016, but most Korean NPPs use the 1984 version (Table 1). Therefore, it is necessary to verify whether the current evaluation system is suitable.
In this study, release rates of target plant(APR-1400) were estimated by applying concentrations of ANSI / ANS-18.1-1976, 1984, 1999, and 2016 to PWR-GALE86.
Table 1. Current Status of South Korea NPPs Anticipated Source Term Nuclear Power Plants ANSI-N237-1976 Kori 1,2, 3, 4 Hanbit 1,2 / Hanul 1,2 ANSI/ANS 18.1-1984 Hanbit 3,4,5,6 Hanul 3,4 5,6 Shin Kori 1,2,3,4 Shin Kori 5,6 PSAR ANSI/ANS 18.1-1999 APR-1400 DCD ANSI/ANS 18.1-2016 None
2. Methodology
2.1. Analysis of ANSI/ANS-18.1 Revision
ANSI/ANS-18.1 provides coolant concentration of the reference PWR. Also it supplies calculation formula and parameter of Adjustment Factor used for
estimating anticipated source term of target plant. Although there are some differences between the revisions, the overall coolant concentration of the reference PWR has decreased since 1984. For Adjustment factor, all are calculated by the same formula since 1984 except for situations where the natural or depleted zinc have been used. (Table 2).
Table 2. Adjustment Factors of Primary Coolant change Element Class 1984 1999, 2016 1 ܲ ή ܹܲή ሺܴଵ ߣሻ ܹܲ ή ܲή ሺܴଵ ߣሻ 2 ܲ ή ܹܲή ሺܴଶ ߣሻ ܹܲ ή ܲή ሺܴଶ ߣሻ 3 ܲ ή ܹܲή ሺܴଷ ߣሻ ܹܲ ή ܲή ሺܴଷ ߣሻ 4 1.0 5 * 6 ܲ ή ܹܲή ሺܴ ߣሻ ܹܲ ή ܲή ሺܴ ߣሻ 6 (Zn-65) ܲ ή ܹܲή ሺܴ ߣሻ ܹܲ ή ܲή ሺܴ ߣሻ 10 6 (Co-58) ܲ ή ܹܲή ሺܴ ߣሻ ܹܲ ή ܲή ሺܴ ߣሻ 10 2.2 PWR-GALE
PWR-GALE86 calculates the release rate of the target NPP based on the information of reference NPP. Since PWR-GALE86 basically uses the information of ANSI / ANS-18.1-1984, the results were derived by applying the information of 1976,1999,2016 version through the change of hardwired parameters.
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2019 ⦽ǎႊᔍᖒ⠱ʑྜྷ⦺⫭⇹ĥ⦺ᚁݡ⫭םྙ᧞Ḳ3. Results and Discussion
3.1 Noble Gas and Halogens
In this case, the change in release rate was the same as the change in coolant concentration of the reference PWR. Release rates decreased sharply except for 133Xe and 131mXe (Fig. 1).
Fig. 1. Release Rate Result for PWR-GALEG.
3.2 Liquid
In the case of PWR-GALEL, 0.16 Ci per NPP is to be adjusted considering the AOO situation. Therefore, the change in release rate is not in perfect agreement with the change in coolant concentrations. However, all nuclides that has big-changed showed the smallest value in the 2016 revision (Fig. 2).
Fig. 2. Release Rate Result for PWR-GALEL.
3.3 Particulates & Specific Nuclides (14C,41Ar,3H)
For particulates and 14C, 41Ar, 3H, PWR-GAEL86 outputs a specified release rate without performing any calculations. This is the average data of the US NPPs in 1970s, so it will need to be additional considered for application to Korea.
4. Conclusion
This study analyzed the expected release rate changes of radioactive effluent from NPP following the ANSI/ANS-18.1 revision.
When the revised version is applied, the estimated release rate is reduced. In order to verify the effectiveness, a comparative analysis with the actual domestic emission data is necessary.
ACKNOWLEDGEMENT
This work was supported by the Nuclear Safety Research Program through the Korea Foundation Of Nuclear Safety (KOFONS), granted financial resource from the Nuclear Safety and Security Commission (NSSC), Republic of Korea (No. 1605008).
REFERENCES
>@ $PHULFDQ 1XFOHDU 6RFLHW\ ³$PHULFDQ 1DWLRQDO Standard Radioactive Source Term for Normal 2SHUDWLRQRI/LJKW:DWHU5HDFWRUV´$16,$16-18.1 (1976,1984,1999,2016)
>@³&DOFXODWLRQRI5HOHDVHVRI5DGLRDFWLYH0DWHULDOV in Gaseous and Liquid Effluents from Pressurized Water Reactors ± PWR-*$/( &RGH´ 185(*-0017 Rev. 1, Nuclear Regulatory Commission (1985)
