ML15040A639
| ML15040A639 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 01/26/2015 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| Download: ML15040A639 (9) | |
Text
Fermi2LRANPEm Resource From: Wentzel, Michael Sent: Monday, January 26, 2015 6:37 AM To: Randall D Westmoreland (westmorelandr@dteenergy.com)
Subject:
Draft Phone Call Summary Attachments: 012315, Summary of Telephone Conference Call Between NRC and DTE Electric Company Concerning Responses to RAIs Pertaining to the Fermi 2 LRA SAMA Review.docx
- Randy, Attached is a draft phone call summary for our call last Friday. Please let me know if you have any comments.
- Thanks, Mike Michael Wentzel Project Manager NRR/DLR/RPB2 (301) 415-6459 michael.wentzel@nrc.gov 1
Hearing Identifier: Fermi2_LR_NonPublic Email Number: 42 Mail Envelope Properties (Michael.Wentzel@nrc.gov20150126063600)
Subject:
Draft Phone Call Summary Sent Date: 1/26/2015 6:36:42 AM Received Date: 1/26/2015 6:36:00 AM From: Wentzel, Michael Created By: Michael.Wentzel@nrc.gov Recipients:
"Randall D Westmoreland (westmorelandr@dteenergy.com)" <westmorelandr@dteenergy.com>
Tracking Status: None Post Office:
Files Size Date & Time MESSAGE 302 1/26/2015 6:36:00 AM 012315, Summary of Telephone Conference Call Between NRC and DTE Electric Company Concerning Responses to RAIs Pertaining to the Fermi 2 LRA SAMA Review.docx 80897 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
Recipients Received:
UNITTED STATES S NUCL LEARREGU ULATORY COMMISSIO C ON WASHINGT TON, D.C. 20555 5-0001 LICENSE EE: DTE Electric E Commpany FACILITY Y: Fermi 2 SUBJEC CT: SUMM MARY OF TE ELEPHONE CONFERENCE CALL HELD ON JA ANUARY 23 3, 2015 BETWEEN B T THE U.S. NU UCLEAR RE EGULATORY COMMISS SION AND DTE D
ELECT TRIC COMP PANY CONC CERNING REQUESTS R FOR ADDIT TIONAL INFOR RMATION PERTAINING G TO THE SEVERE ACC CIDENT MIT TIGATION ALTER RNATIVES REVIEW R OFF THE FERM MI 2LICENSE RENEWA AL APPLIICATION The U.S.. Nuclear Re egulatory Co ommission (N NRC) and re epresentativees of DTE Electric Companyyheld a telep phone confe erence call on o January 23, 2 2015, to discuss d and clarify the NRC N
staffs req quests for additional infoormation (RA AIs) concern ning the Ferm mi 2 license renewal applicatioon severe acccident mitiggation alternaatives review w. The telepphone confe erence call was w
useful in identifying areas a where further inforrmation wass necessary.
Enclosurre 1 provides ants and Enclosure 2 co s a listing of the participa ontains a listing of the RAAIs discusse ed with the applicant, inccluding a brieef description on the stattus of the ite ems.
The applicant had an n opportunityy to commen nt on this summary.
Michael We entzel Projects Bra anch 2 Division of License L Rennewal Office of Nu uclear Reacttor Regulatioon Docket Number:50-3 N 341 Enclosurres:
As stated d cc w/enccls: See nex xt page
OFFICE LA:DLR PM:RPB2:DLR BC:RPB2:DLR PM:RPB2:DLR NAME M Wentzel B Wittick M Wentzel DATE / / / / / / / /
TELEPHONE CONFERENCE CALL FERMI 2LICENSE RENEWAL APPLICATION SEVERE ACCIDENT MITIGATION ALTERNATIVES LIST OF PARTICIPANTS JANUARY 23, 2015 PARTICIPANTS AFFILIATIONS Jerry Dozier U.S. Nuclear Regulatory Commission (NRC)
Michael Wentzel NRC Roland Benke Center for Nuclear Waste Regulatory Bob Schmidt CNWRA Michael Koenemann DTE Electric Company (DTE)
Michael Lake DTE Kevin Lynn DTE Randall Westmoreland DTE Chad Kramer Enercon Brian Norman Enercon Gary Smith Enercon Joe Lavelline Maracor/Enercon Alex Duvall ERIN Engineering Grant Teagarden ERIN Engineering Enclosure 1
REQUESTS FOR ADDITIONAL INFORMATION FERMI 2 LICENSE RENEWAL APPLICATION SEVERE ACCIDENT MITIGATION ALTERNATIVES JANUARY 23, 2015 The U.S. Nuclear Regulatory Commission (NRC) and representatives of DTE Electric Company(DTE) held a telephone conference call on January 23, 2015, to discuss and clarify the following requests for additional information (RAIs) concerning the Fermi 2 license renewal application severe accident mitigation alternatives (SAMA) review.
Regarding Response to RAI 1.c.iii What is the value for the phenomenological failure probability of the common cause failure of all four combustion turbine generators in the event of a weather centered loss of the 345kV (Division 2) Switchyard?
Discussion: DTE indicated that the question is clear.
Regarding Response to RAI 2.g.iii The RAI response provided a wealth of information supporting the selection of representative sequences in terms of the determination of the base case risk, however, the impact of representative selection on the calculation of delta risk for a SAMA is not specifically addressed.
Furthermore, the information provided indicates that the specific example in the RAI will not adversely impact the selection of cost-beneficial SAMAs; however, it does raise concern about the impact of combining Class IIA sequences with Class IV sequences. As indicated in the RAI response, separating the Class IIA sequences from the Class IV sequences in the H/E release category results in a 15% increase in dose risk and a 0.6% increase in OECR in the total risk.
Table 2.g-4 indicates the revised Class II contribution is 2.69 times the person-rem/yr and 1.08 times the OECR contributions when they are included in the H/E base case release category.
Thus, the staff believes, the benefit of any SAMA that significantly reduces the risk of Class IIA (loss of containment heat removal) sequences will be underestimated. Please address the impact of combining Class IIA sequences with Class IV sequences and clarify the impact of representative selection on the calculation of delta risk for a SAMA.
Discussion: DTE indicated that the question is clear.
Regarding Response to RAI 2.e The SAMA analysis release category frequency is based upon a truncation of 1E-12/yr which results in undercounting the Class II frequency by 3.14E-09/yr compared to the Class II frequency from the Level 1 quantification. This is stated to have been resolved by lowering the truncation to 1E-14/yr. It is stated that this 3.14E-09/yr difference was added to the PRA documentation release category (RC) medium/early (M/E) frequency but not that used in the SAMA analysis. What was the basis for assigning this undercounting due to truncation to RC M/E and not other RCs such as high/early (H/E)? Was it based on the results of the Level 2 quantification at the lower truncation?
Enclosure 2
Discussion: Based on the discussion with DTE, the NRC staff modified the draft request, as follows, to make clear the information that the NRC staff is requesting:
The SAMA analysis release category frequency is based upon a truncation of 1E-12/yr which results in undercounting the Class II frequency by 3.14E-09/yr compared to the Class II frequency from the Level 1 quantification. This is stated to have been resolved by lowering the truncation to 1E-14/yr. It is stated that this 3.14E-09/yr difference was added to the PRA documentation release category (RC) medium/early (M/E) frequency but not that used in the SAMA analysis. Discuss the basis for assigning this undercounting due to truncation to RC M/E and not other RCs such as high/early (H/E) and the impact of not including these truncated out Class II cutsets in the evaluation of the benefit for the SAMAs.
Regarding Response to RAI 4.c The economic multiplier stated in the RAI response is 2.1384 which is different from the value of 1.2964 stated on page D-96 of the environmental report (ER). The RAI response does not mention any reason for the ER value to be different from the original value. Please clarify which is the correct value for the economic multiplier value(s) used in the assessment of cost beneficial SAMAs.
Discussion: DTE indicated that the question is clear.
Regarding Response to RAIs 5.a.ii, 5.a.vi, 5.a.vii, 6.h and 7.a The response to these RAIs provides the result of new cost benefit analyses. Was this based on doing the complete analysis similar to that for the ER evaluation involving determining the new release category frequencies and resulting cost risks, or were some assumptions made? Some of the results do not appear to be consistent with those given in Table D.2-1. Are these results conservative?
Discussion: DTE indicated that the question is clear.
Regarding Response to RAI 6.c While Fermi 2 may not have the same vulnerability that prompted SAMA 023 to develop procedures to repair or replace failed 4 kV breakers, this SAMA was cited to mitigate a number of important Fermi events in Table D.1-2 and screening it out is not considered appropriate. If the transfers cited in the source of this SAMA are not required, why were they cited in the evaluation of the benefit of SAMA 023?
Discussion: Based on the discussion with DTE, the NRC staff modified the draft request, as follows, to make clear the information that the NRC staff is requesting:
While Fermi 2 may not have the same vulnerability that prompted SAMA 023 to develop procedures to repair or replace failed 4 kV breakers, this SAMA was cited to mitigate a number of important Fermi events in Table D.1-2 and screening it out is not considered appropriate.
Evaluate the benefit of a procedure to develop or replace failed 4 kV breakers where ever it may be of a benefit at Fermi 2.
Regarding Response to RAI 6.e Enclosure 2
The response indicates that assuming a 15% reduction in main steam isolation valves (MSIVs) failure to close and safety relief valves (SRVs) failure to open has essentially no impact (~<0.01) on risk. On the other hand, operator failures to depressurize have risk reduction worths of 1.10, 1.05, and 1.03. These are equivalent to SRVs failure to open and would indicate that the above reduction in SRV failure to open would lead to a 2% reduction in CDF. Please clarify this disparity.
Discussion: Based on the discussion with DTE, the NRC staff modified the draft request, as follows, to make clear the information that the NRC staff is requesting:
The response indicates that assuming a 15% reduction in main steam isolation valves (MSIVs) failure to close and safety relief valves (SRVs) failure to open has essentially no impact (~<0.01) on risk. On the other hand, operator failures to depressurize have risk reduction worths of 1.10, 1.05, and 1.03. These are equivalent to SRVs failure to open and would indicate that the above reduction in SRV failure to open would lead to a 2% reduction in CDF. Please discuss the MSIV and SRV hardware failure modeling characteristics included in the Fermi 2 PRA that lead to this very small risk impact.
Enclosure 2
SUBJECT:
Summary of Telephone Conference Call conducted on January 23, 2015 DISTRIBUTION:
HARD COPY:
DLR RF E-MAIL:
PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRpb2 Resource RidsNrrDlrRerb Resource RidsNrrDlrRarb Resource RidsNrrDlrRasb Resource RidsNrrDlrRsrg Resource RidsNrrPMFermi Resource DMeléndez-Colón MWentzel YDiaz-Sanabria BWittick JDozier UShoop BHarris, OGC MKunowski, RIII BKemker, RIII PSmagacz, RIII VMitlyng, RIII PChandrathil, RIII HLogaras, RIII ABarker, RIII Enclosure 2