ML110400510

1/19/11 Summary of Telephone Conference Call Held Between USNRC and Energy Northwest Concerning Requests for Additional Information Pertaining to the SAMA Review of the Columbia Generating Station License Renewal Application

ML110400510
Person / Time
Site:	Columbia
Issue date:	03/01/2011
From:	Dan Doyle License Renewal Projects Branch 1
To:
Doyle D, NRR/DLR, 415-3748
References
Download: ML110400510 (11)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 March 1, 2011 LICENSEE: Energy Northwest FACILITY: Columbia Generating Station SUB"IECT:

SUMMARY

OF TELEPHONE CONFERENCE CALL HELD ON JANUARY 19, 2011, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND ENERGY NORTHWEST CONCERNING REQUESTS FOR ADDITIONAL INFORMATION PERTAINING TO THE SEVERE ACCIDENT MITIGATION ALTERNATIVES REVIEW OF THE COLUMBIA GENERATING STATION LICENSE RENEWAL APPLICATION The U.S. Nuclear Regulatory Commission and representatives of Energy Northwest (the applicant) held a telephone conference call on January 19, 2011, to discuss the applicanfs draft response to requests for additional information concerning the Severe Accident Mitigation Alternatives review of the Columbia Generating Station license renewal application. provides a list of the participants and Enclosure 2 contains a list of the comments on the draft response including a brief description of the status of the items.

The applicant had an opportunity to comment on this summary.

~ Daniel I. Doyle, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-397

Enclosures:

1. List of Participants

2. List of Comments on Draft Response cc w/encls: Distribution via Listserv

LIST OF PARTICIPANTS COLUMBIA GENERATING STATION LICENSE RENEWAL APPLICATION SEVERE ACCIDENT MITIGATION ALTERNATIVES REVIEW TELEPHONE CONFERENCE CALL JANUARY 19, 2011 PARTICIPANTS AFFILIATIONS Daniel Doyle U.S. Nuclear Regulatory Commission (NRC)

Ray Gallucci NRC Arthur Cunanan NRC Steve Short Pacific Northwest National Laboratory (PNNL)

Garill Coles PNNL Bruce Schmitt PNNL Abbas A. Mostala Energy Northwest (EN)

Jim Tansy EN Albert T. Chiang EN Jerral E. "Dusty" Rhoads EN Lisa Williams EN Eric J. Jorgenson Maracor Stanley Levinson AREVA James Metcalf AREVA Darvin Kapitz AREVA Jennifer Butler AREVA Larry Lee ERIN Engineering ENCLOSURE 1

REQUESTS FOR ADDITIONAL INFORMATION COLUMBIA GENERATING STATION LICENSE RENEWAL APPLICATION SEVERE ACCIDENT MITIGATION ALTERNATIVES REVIEW JANUARY 19, 2011

Background:

The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of the applicant, Energy Northwest (EN), held a telephone conference call on January 19, 2011! to discuss comments on the applicant's draft response to requests for additional information (RAls) concerning the Severe Accident Mitigation Alternatives (SAMA) review of the Columbia Generating Station (CGS) license renewal application (LRA).

The NRC issued a previous RAI related to the SAMA review to EN by letter dated July 1, 2010 (ADAMS Accession Number ML101760421). EN provided a partial response to the RAls by letter dated September 17, 2010 (ADAMS Accession Number ML102660151). The NRC issued two sets of clarification RAls by letters dated November 10, 2010 (ADAMS Accession Number ML102870984) and December 2,2010 (ADAMS Accession Number ML103330246).

The purpose of this telephone conference was to address comments from the staff on EN's draft RAI response intended to close out the SAMA RAls.

Comments:

Comment 1:

Table A-10 shows CB-08 and CB-09 subsumed by CB-01 (inconsistent with response to RAI 6.b 09-17-2010). While the environmental report (ER) and Table 6.j-1ii-1 provided estimated benefits of $0, for these SAMAs, same as CB-01, sensitivity analysis shows CB-01 benefit to be $20K. Since CB-08 and CB-09 have lower implementation cost than CB-01, they will be treated as evaluated (Case 09) and not subsumed, and both appear to be cost beneficial using the sensitivity analysis results for CB-01.

Discussion:

The entries referencing SAMA candidates CB-08 and CB-09 will be clarified. CB-08 and CB-09 will be evaluated for cost-benefit using probabilistic safety assessment (PSA) Rev. 7.1 to be consistent with what was done for PSA Rev. 6.2. (See Tables B-1 through B-8.)

Comment 2:

For SAMAs that increase risk (core damage frequency (CDF), dose, OECR), explain. e.g.

AC/DC-30R (internal events), CC-25R (fire events), SR-05R (seismic events).

ENCLOSURE 2

-2 Discussion:

Any increase in risk, not just an increase in the overall total, will be discussed. (See Tables B-2 through B-5, B-7, and B-B.)

Comment 3:

Editorial: Table B-2 occasionally messed up (Le., page 125, 127).

Discussion:

Table will be corrected. (See Table B-2.)

Comment 4:

Minor: Table B-6 footnotes - Can't determine reason for differences between footnotes.

Presumably each reflects different RAI responses?

Discussion:

The footnotes are correct as-is even though each is the same (with the exception of the specific SAMA candidates identified). There is no reason for the different footnotes.

Comment 5:

Explain how benefit estimates for 3% Sensitivity Case #1 are calculated. NRC staff results are higher than reported in Table B-B. For example, for internal events, the following are calculated at 3%: APE - $23BK, AOC - $153K, AOE - $6.7K, cleanup/decontamination - $211 K, and replacement power - $217K for total of internal events MACR of $B23K.

Discussion:

EN requested a copy of the NRC's spreadsheet in which the 3% discount rate sensitivity case was performed so that EN could understand and explain any difference in the approach taken for this sensitivity case. (See footnote added to Table B-B.)

Comment 6:

SAMAs CC-01 (Case 10) and CC-02 (Case 11) report exact same benefits, but model approaches described in ER Table E.11-1 are different. Confirm that the model approaches described for each were used in the SAMA evaluation and produce identical results.

Discussion:

Clarification will be added that the same model approach was used for both SAMAs even though the description of each model approach is different. (See footnote added to Table B-1.)

- 3 Comment 7:

Editorial: Table 6.j-1 ii-1 estimated benefit value for FR-07a is $1,034,480, not $1,304,480.

Discussion:

Table will be corrected. (See Table 6.j-1 ii-1.)

Comment 8:

Description of model approach for new SAMAs in Table 8-1 need to be modified/expanded to be put into layman terms (e.g., FL-05R).

Discussion:

Additional information for some of the entries on Table 8-1 will be provided. (See Table 8-1, SAMA candidates SR-05R through C8-10R.)

Comment 9:

Confirm that basic modeling approach for SAMAs used in the sensitivity analysis (Table 8-1) remained the same as that described in the ER (Table E.11-1). For example, it is observed for FR-03 that while the basic modeling approach remained unchanged (probability of most risk significant hot shorts set to 0), the specific modeling change was revised slightly presumably because the risk significant hot shorts changed in model Rev. 7.1.

Discussion:

Clarification will be added that the modeling approach for SAMA candidates in Table 8-1 remained the same as that described in the ER (Table E.11-1). (See footnote added to Table 8-1.)

Comment 10:

Editorial: Table A-13 values for RRW and point estimate missing.

Discussion:

Table will be corrected. (See Table A-13.)

- 4 Comment 11:

Page 3 states that "Table A-1 provides the changes in CDF for Rev. 7.1 relative to Rev. 6.2 for all initiating events, along with a characterization of the changes in terms of plant changes and the Internal Events and Flooding upgrade to RG 1.200 Rev. 2." Sequences identified in Table A-1 appear to be internal events sequences. Differences shown between Rev 7.1 and Rev 6.1 CDFs appear to be related to specific improvements made to the model and related to trying to comply with RG 1.200.

a. Describe the source of the model changes (e.g., facts and observations (F&Os) from internal or external peer review comments).

b. Confirm what parts of the PSA model the changes apply to (Le., whether the changes were only to the Level 1 Internal Events model).

c. Explain why the Fire Events CDF appears to have increased significantly as a result of changes to the internal events model.

d. Provide a table similar to A-1 and A-2 that addresses fire and seismic initiators.

Discussion:

a & b. High level discussion on the source of the model changes will be added. Changes were made only to Levels 1 and 2 PSAs for internal events, plus the internal events Level 2 CETs were integrated with the fire and seismic models. (See Section 2.0.)

c. & d. Tables for Fire and Seismic CDF will be added. When addressing the "LOCA signal" and MSIV HVAC, the fire CDF ended up being doubled. (See Tables A-1 (Fire) and A-1 (Seismic).)

Comment 12:

Table 3.d(i)-1 presents the change in RRW value for four selected SAMAs as a way to demonstrate that conduit modeling incompleteness has marginal effect on the SAMA evaluation. Provide the rationale for the SAMAs selected. Provide justification for why these SAMAs are representative or bounding related to the other SAMAs including the "installation of early detection in fire area" SAMAs.

Discussion:

Additional SAMA candidates (FR-OSR and FR-12R) will be added to the table. Also, the following typographical error was noted - the RRW for FR-11 R should have been 1.067. (See Table 3.d(i)-1.)

Comment 13:

In Table A-S, a number of operator error events with RRW values higher than 1.01 are presented (e.g., ATWH-HPLPRSTH3XX, RHRH-ATWSDC-H3XX, TSWHUMNIC525H3LL, TSWHUMNIC502H3L, HPS-CTL-COND----, ADSHUMNSTARTH3LT, RHRHUMNSYS62H3LL, SW-HUMN-W521 H3LL, XDPHUMN-W521 H3LL). Procedure improvements for these events are not discussed as a potential mitigation strategy. In light of this, and the response to RAI 5.3,

- 5 explain how procedure improvements were considered in the SAMA evaluation, especially for the identified events.

Discussion:

For these operator error events, clarification will be added to indicate that "improved training" includes procedural enhancements. (See revised discussion concerning SAMA candidate OT-07R.)

Comment 14:

Table A-11 presents a Level 1 basic fire events importance list which appears to be significantly different from the list presented in Table 5.d-1 of the response to RAls transmitted September 17,2010. For example events labeled "GTFF", "GTFF50", and "GTFF10" appear at the top of the list in Table A-11 but did not appear at all in the earlier list (i.e., Table 5.d-1).

Explain the difference in the modeling that produced this different listing.

Discussion:

The sorting criterion used to create Table 5.d-1 was different than that for Table A-11. Sorting for Rev. 6.2 used RAW first, followed by an RRW sort. Rev. 7.1 sorted directly on RRW. If Table 5.d-1 was sorted purely by RRW, then the events GTFF, GTFF50 and GTFF10 would have appeared in the table. (See footnote added to Table A-11.)

Comment 15:

Response to RAI 3.i What is the value used for internal events CCF of the MSIVs to isolate?

Does this value bound the probability of a fire-induced ISLOCA (e.g., spurious opening of two

=

series MOVs due to hot shorting - 0.31\2 0.09)?

Discussion:

Discussion will be added to address this question. (See response for RAI 3.i-1.)

Comment 16:

Tables A-3, A-4, and A While the LERF (HIE release category) frequency decreased by a factor of 2 for internal and seismic events, it decreased by a factor of 6 for fire events. Explain.

Discussion:

A footnote will be added to clarify that fire LERF is dominated by normal loss of injection, not ATWS. (See Table A-4.)

-6 Comment 17:

Tables A-15 and A The implementation cost estimates for the following Phase I SAMAs were substantially increased based on a CGS-specific cost estimate: AT-10, CC-12, CP-12, CP-22, and CP-24. Provide justification for the cost estimate developed for these SAMAs (e.g.,

breakdown of the costs to the level of detail estimated).

Discussion:

A breakdown of costs for the identified SAMA candidates will be provided. (See Section 4.3.)

Comment 18:

Table A SAMA IA-03 was screened based on the risk reduction from removing the TSW dependency. Does this analysis bound the risk reduction from adding additional air compressors?

Discussion:

A case will be evaluated for adding a new compressor. (It was determined that existing SAMA candidate IA-02 evaluates adding air compressors. See Table A-16.)

Comment 19:

Section 2.4 - Provide explanation of the weighting performed on "dominant cutsets and associated MMP cases" to determine the representative MMP cases. It is unclear how this addresses low frequency, high consequence sequences.

Discussion:

For the two extremes (High Early vs. Low Late), release estimates were based on the dominant scenarios and their corresponding MMP results, with the release estimates weighted by the scenario frequencies. Discussion/example will be provided. (See Section 2.4.)

Additional Comment 1:

In Table 4-2, the entry for CW-07 includes fire LERF. However, Note 2 does not indicate that this was included. Please make this consistent.

Discussion:

The table entry is correct (fire LERF was included), and the Note will be clarified.

-7 Additional Comment 2:

Several Phase I SAMAs were dispositioned in Table A-16 by dividing the total estimated benefit by the number of trains/components to argue that the benefit is less than $100K and therefore the SAMA is screened on Criterion E, Very Low Benefit. This is not an acceptable approach to screening, the entire risk benefit must be considered in the evaluation.

Discussion:

The Phase I screening for these SAMAs will be re-evaluated based on the total risk reduction benefit.

'-. ML110400510 OFFICE LA:DLR PM:RPB1 :DLR I BC:RPB1:DLR PM:RPB1 :DLR NAME YEdmonds DDoyle BPham DDoyle I DATE 02/15/11 02/18111 03/01/11 03/01/11

Memorandum to Energy Northwest from D. Doyle dated March 1 2011

SUMMARY

OF TELEPHONE CONFERENCE CALL HELD ON JANUARY 19, 2011, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND ENERGY NORTHWEST CONCERNING REQUESTS FOR ADDITIONAL INFORMATION PERTAINING TO THE SEVERE ACCIDENT MITIGATION ALTERNATIVES REVIEW OF THE COLUMBIA GENERATING STATION LICENSE RENEWAL APPLICATION DISTRIBUTION:

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