ML18002A558

Korea Hydro & Nuclear Power Co., Ltd - Response to RAI Er 3-8655 for Question EA ACC/SAMDA-1

ML18002A558
Person / Time
Site:	05200046
Issue date:	01/02/2018
From:	Korea Hydro & Nuclear Power Co, Ltd
To:	Office of New Reactors
Shared Package
ML18002A556	List: ML18002A557 ML18002A558
References
MKD/NW-18-0006L
Download: ML18002A558 (3)

Text

EA ACC/SAMDA 1 / 3 KEPCO/KHNP RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION APR1400 Design Certification Korea Electric Power Corporation / Korea Hydro & Nuclear Power Co., LTD Docket No.52-046 RAI No.: ER 3-8655 SRP Section: Environmental Report Application Section: APR1400 Environmental Report Date of RAI Issued: 11/30/2016 Question No. EA ACC/SAMDA-1 On May 4, 2016, the Commission issued a decision (CLI-16-07; Agency-wide Documents Access and Management System (ADAMS) Accession No. ML16125A150) in the Indian Point license renewal proceeding. The Commission found that none of the parties involved in the Indian Point Severe Accident Mitigation Alternatives (SAMA) contention could provide a documented description outlining the technical foundation for two inputs (the time to decontaminate, TIMDEC, and the cost to decontaminate non-farmland, CDNFRM) used in the MACCS computer analyses. It was noted by the Commission that sensitivity analyses help demonstrate whether and to what extent variations in an uncertain input value might affect the overall cost-benefit conclusions. The Commission therefore directed the Staff to perform additional sensitivity analyses varying the TIMDEC and CDNFRM input parameters using specific values.

The TIMDEC and CDNFRM parameters used in the Indian Point SAMA analysis are also commonly used in the off-site risk calculations applied in the Severe Accident Mitigation Design Alternatives (SAMDA) cost-benefit analyses performed for new reactor standard design certification and combined license applications. These two input values were generally based on the values provided in NUREG 1150, Severe Accident Risks: An Assessment for Five U.S.

Nuclear Power Plants, and NUREG/CR-3673, Economic Risks of Nuclear Power Reactor Accidents. The TIMDEC input value defines the time required for completing decontamination to a specified degree. The CDNFRM input parameter defines the cost (on a per person basis) of decontaminating non-farmland by a specified decontamination factor. The input values applied are set based on the level of contamination as specified by the decontamination factor parameter, DF. The CDNFRM values used in NUREG-1150 stem from decontamination cost estimates provided in NUREG/CR-3673, the same 1984 economic risk study referenced in support of the decontamination time inputs. These decontamination cost inputs are commonly set to specific values associate with different levels of contamination and escalated to account for inflation.

EA ACC/SAMDA 2 / 3 KEPCO/KHNP The SAMDA analysis performed for the Advanced Power Reactor 1400 (APR1400) Standard Design Certification (DC) also relied upon the NUREG-1150 values for TIMDEC and CDNFRM.

Therefore, the staff requires the applicant to justify why the TIMDEC and CDNFRM parameters used in the SAMDA analysis for the APR1400 DC are acceptable or perform a cost-benefit sensitivity analyses based on revised TIMDEC and CDNFRM values for the applied DF levels.

If sensitivity analyses will be performed, use input values for the sensitivity analysis either (1) based on information in CLI-16-07 for the appropriate sets of DF values or, in the alternative, (2) selected by the applicant and appropriately justified for the sensitivity analyses. Since two decontamination levels are currently assessed in the APR1400 MACCS calculation (i.e., low contamination levels with a DF=3 and high contamination levels with a DF=15), apply a set of maximum values for a DF=3 and another set of maximum values for a DF=15. Explain with sufficient justification your appropriate maximum values for TIMDEC and CDNFRM for each DF value. With the revised values, re-assess the offsite risks and apply the revised results into the SAMDA cost-benefit analysis for a revised maximum averted costs. Determine if there is now a SAMDA that could be cost-beneficial based on the revised decontamination inputs and justify the resulting determination.

Upon completing the analyses, document the sensitivity analyses in an appropriate manner in the APR1400 Standard Design Certification Environmental Report and related technical document(s).

Response

The sensitivity analysis was performed and discussed in Case 10 of the Level 3 Analysis in Appendix A of the SAMDA Report (APR1400-E-P-NR-14006-P, Rev. 1). Parameter TIMDEC was increased to 3.15x107 seconds (365 days) and CDNFRM was increased to 1x105 $/person.

The sensitivity results for this case, when compared to the base case dose increased slightly in dose and more significantly in offsite economic cost.

When applied to the Level 2 at-power internal events STC frequencies, the change in dose increased from 5.33x10-1 REM/yr to 5.63 x10-1 REM/yr. Offsite economic costs increased from $1,534 to $3,466. With this dose and dollars applied to the other at-power and LPSD results, the total averted costs (TAC) increased from $909,168 to $986,940 (increase of $77,000) for this sensitivity case and 7% discounted rate. For the 3% discounted rate, TAC increased from $964,323 to $1,118,107 (increase of $154,000). The increase in dose of approximately 5%

and the increase in the TAC of approximately 15% due to the change in these parameters would not impact the overall conclusion of the SAMDA Report.

For the Level 3 analysis, the analysis does not use or reference the Level 2 STC frequencies that are in the SAMDA analysis. The sensitivity results show the general increase in values over the base case.

Impact on DCD There is no impact on the DCD.

EA ACC/SAMDA 3 / 3 KEPCO/KHNP Impact on PRA There is no impact on the PRA.

Impact on Technical Specifications There is no impact on the Technical Specifications.

Impact on Technical/Topical/Environmental Reports The SAMDA Report is updated to reflect the changes discussed above.