ML080230728

Request for Additional Information Regarding Severe Accident Mitigation Alternatives for Beaver Valley Power Station, Units 1 and 2, License Renewal

ML080230728
Person / Time
Site:	Beaver Valley
Issue date:	01/28/2008
From:	Kent Howard NRC/NRR/ADRO/DLR/REBA
To:	Sena P FirstEnergy Nuclear Operating Co
Sayoc, Manny, NRR/DLR/RLRB 415-1924
References
TAC MD6595, TAC MD6596
Download: ML080230728 (11)

Text

January 28, 2008 Peter P. Sena III Site Vice President FirstEnergy Nuclear Operating Company Beaver Valley Power Station Mail Stop A-BV-SEB-1 P.O. Box 4, Route 168 Shippingport, PA 15077

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING SEVERE ACCIDENT MITIGATION ALTERNATIVES FOR BEAVER VALLEY POWER STATION UNITS 1 AND 2 LICENSE RENEWAL (TAC NOS. MD6595 and MD6596)

Dear Mr. Sena:

The U.S. Nuclear Regulatory Commission (NRC or staff) has reviewed the Severe Accident Mitigation Alternatives (SAMA) analysis submitted by FirstEnergy Nuclear Operating Company, regarding its application for license renewal for Beaver Valley Power Station Units 1 and 2, and has identified areas where additional information is needed to complete its review. Enclosed is the staff=s request for additional information (RAI).

We request that you provide your responses to these questions within 30 days of the date of this letter, in order to maintain the license renewal review schedule. If you have any questions, please contact me at 301-415-2989 or at KLH1@nrc.gov.

Sincerely,

/RA/

Kent Howard License Renewal Project Manager Projects Branch 2 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-334 and 50-412

Enclosure:

As stated cc w/encl: See next page

January 28, 2008 Peter P. Sena III Site Vice President FirstEnergy Nuclear Operating Company Beaver Valley Power Station Mail Stop A-BV-SEB-1 P.O. Box 4, Route 168 Shippingport, PA 15077

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING SEVERE ACCIDENT MITIGATION ALTERNATIVES FOR BEAVER VALLEY POWER STATION UNITS 1 AND 2 LICENSE RENEWAL (TAC NOS. MD6595 and MD6596)

Dear Mr. Sena:

The U.S. Nuclear Regulatory Commission (NRC or staff) has reviewed the Severe Accident Mitigation Alternatives (SAMA) analysis submitted by FirstEnergy Nuclear Operating Company, regarding its application for license renewal for Beaver Valley Power Station Units 1 and 2, and has identified areas where additional information is needed to complete its review. Enclosed is the staff=s request for additional information (RAI).

We request that you provide your responses to these questions within 30 days of the date of this letter, in order to maintain the license renewal review schedule. If you have any questions, please contact me at 301-415-2989 or at KLH1@nrc.gov.

Sincerely,

/RA/

Kent Howard License Renewal Project Manager Projects Branch 2 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-334 and 50-412

Enclosure:

As stated cc w/encl: See next page DISTRIBUTION: See next page Adams Accession No. ML080230728 OFFICE LA:DLR PM:ADES:DRA PM:DLR:RPB2 PM:DLR:RPB2 BC:DLR:RPB2 NAME SFigueroa RPalla ESayoc KHoward RFranovich DATE 01/24/08 01/28/08 01/24/08 01/28/08 01/28/08 OFFICIAL RECORD COPY

Letter to Pete Sena III from Kent Howard dated January 28, 2008 DISTRIBUTION:

SUBJECT:

REQUEST FOR LIST OF PROTECTED SPECIES WITHIN THE AREA UNDER EVALUATION FOR THE BEAVER VALLEY POWER STATION, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION REVIEW E-MAIL:

PUBLIC SSmith (srs3)

SDuraiswamy RidsNrrDlr RidsNrrDlrRlra RidsNrrDlrRlrb RidsNrrDlrRlrc RidsNrrDlrReba RidsNrrDlrRebb RidsNrrDciCvib RidsNrrDciCpnb RidsNrrDraAfpb RidsNrrDeEmcb RidsNrrDeEeeb RidsNrrDssSbwb RidsNrrDssSbpb RidsNrrDssScvb RidsOgcMailCenter KHoward ESayoc PBuckberg NMorgan MModes, RI PCataldo, RI DWerkheiser, RI

Beaver Valley Power Station cc:

Joseph J. Hagan President and Chief Nuclear Officer FirstEnergy Nuclear Operating Company Mail Stop A-GO-19 76 South Main Street Akron, OH 44308 James H. Lash Senior Vice President of Operations and Chief Operating Officer FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 Danny L. Pace Senior Vice President, Fleet Engineering FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 Jeannie M. Rinckel Vice President, Fleet Oversight FirstEnergy Nuclear Operating Company Mail Stop A-GO-14 76 South Main Street Akron, OH 44308 David W. Jenkins, Attorney FirstEnergy Nuclear Operating Company Mail Stop A-GO-15 76 South Main Street Akron, OH 44308 Manager, Fleet Licensing FirstEnergy Nuclear Operating Company Mail Stop A-GO-2 76 South Main Street Akron, OH 44308 Ohio EPA-DERR ATTN: Zack A. Clayton P.O. Box 1049 Columbus, OH 43266-0149 Director, Fleet Regulatory Affairs FirstEnergy Nuclear Operating Company Mail Stop A-GO-2 76 South Main Street Akron, OH 44308 Manager, Site Regulatory Compliance FirstEnergy Nuclear Operating Company Beaver Valley Power Station Mail Stop A-BV-A P.O. Box 4, Route 168 Shippingport, PA 15077 Commissioner James R. Lewis West Virginia Division of Labor 749-B, Building No. 6 Capitol Complex Charleston, WV 25305 Director, Utilities Department Public Utilities Commission 180 East Broad Street Columbus, OH 43266-0573 Director, Pennsylvania Emergency Management Agency 2605 Interstate Dr.

Harrisburg, PA 17110-9364 Dr. Judith Johnsrud Environmental Coalition on Nuclear Power Sierra Club 433 Orlando Avenue State College, PA 16803 Director Bureau of Radiation Protection Pennsylvania Department of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469

Beaver Valley Power Station cc:

Mayor of the Borough of Shippingport P.O. Box 3 Shippingport, PA 15077 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 298 Shippingport, PA 15077 Cliff Custer FirstEnergy Nuclear Operating Company Beaver Valley Power Station P.O. Box 4, Route 168 Shippingport, PA 15077 Mike Banko FirstEnergy Nuclear Operating Company Beaver Valley Power Station P.O. Box 4, Route 168 Shippingport, PA 15077 Julie Firestone FirstEnergy Nuclear Operating Company Beaver Valley Power Station P.O. Box 4, Route 168 Shippingport, PA 15077

Request for Additional Information Regarding the Analysis of Severe Accident Mitigation Alternatives (SAMAs) for Beaver Valley Units 1 and 2 License Renewal]

1.

Provide the following information regarding the Probabilistic Risk Assessment (PRA) models used for the SAMA analysis (for both units unless otherwise specified):

a.

The list of dominant contributors to core damage frequency (CDF) only accounts for 90 percent of the internal events CDF. Provide the complete CDF breakdown of the remaining initiating events.

b.

Clarify whether anticipated transient without scram (ATWS) events are modeled in the external event analysis. Provide the ATWS and station blackout (SBO) CDF for both internal and external event initiators.

c.

Provide a discussion on the loss of containment instrument air. Identify any differences in plant features or PRA models/assumptions that cause the loss of containment instrument air initiator (ICX) to be a larger contributor in Unit 2 than Unit 1.

d.

Significant CDF reduction was achieved as a result of Revision 3 update for Unit 1, i.e., a reduction in internal event CDF from 6.24E-5 per year in Revision 2 to 7.45E-6 per year in Revision 3. Discuss the reasons for the reduction in CDF and the extent to which these changes were considered in the Westinghouse Owners Group peer review.

e.

It is indicated that the heat up rates for the switchgear rooms is slower than what was assumed during the Individual Plant Examination (IPE). The heatup times are now about 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> in Unit 1 (per discussion of SAMA 181 in Table 6-1) and more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in Unit 2 (per discussion in Section 3.1.1.2). Describe the plant features or modeling that causes the difference in heat up rates between the units.

f.

Discuss the peer reviews performed (internal and/or external to FENOC) and quality controls applied to the external event models, to the Level 2 PRA models, and to the internal event PRA revisions subsequent to the Westinghouse Owners Group and Nuclear Energy Institute peer reviews (i.e., Revisions 3 and 4 for Unit 1 and Revisions 3B and 4 for Unit 2.)

g.

Identify the major shared systems and components between the two units.

Discuss how their risk contributions are accounted for in the PRA.

h.

Provide the CDF for internal floods and provide a breakdown and summary of the top flood scenarios.

2.

Provide the following information relative to the Level 2 PRA analysis:

a.

According to Table 3.4.3-2, there are ten release categories plus an intact containment category which are used for the SAMA case runs. Provide a description of the fission product release fractions used for the MACCS2.

Enclosure

b.

It is noted that MAAP-DBA was used to support the Level 2 analysis rather than the more widely-used MAAP 4.0.4 computer code. Discuss the rationale for using MAAP-DBA and the estimated impact of this code choice on accident progression and source terms. Provide a comparison of the source terms obtained using MAAP-DBA with source terms based on MAAP 4.0.4 for comparable sequences.

c.

In Section 3.2.1 it is stated that it is not necessary to run a MAAP-DBA case to represent each individual release class. For example, for Release Type I, release categories BV1, BV3, BV18, and BV19 were re-analyzed, but BV2 and BV4 were not. Explain why the MAAP-DBA reanalysis was performed for only a subset of the release categories, how this subset was selected, and how the remaining release categories were treated.

3.

Provide the following information regarding the treatment of external events in the SAMA analysis:

a.

Confirm which versions of the internal events PRA were used to develop the fire CDF values reported in Table 3.1.2.1-1. Provide a summary of the dominant fire scenarios for the current fire model in terms of overall fire frequency, plant initiator, and structures, systems, and components (SSCs) impacted.

b.

Provide a summary of the dominant seismic scenarios for the current seismic model in terms of overall seismic initiator frequency, plant initiator, and SSCs impacted.

4.

Provide the following information concerning the MACCS2 analyses:

a.

The MACCS2 economic input values provided in Section 3.4.2 are based on Scientech Calculation 17676-0002, Beaver Valley Power Station MACCS2 Input Data, (Reference 33), and exceed the values provided in NEI 05-01, Severe Accident Mitigation Alternatives (SAMA) Analysis Guidance Document, by about 15 to 70 percent. Provide a copy of this reference.

b.

Three problems related to use of the SECPOP2000 code have recently been identified, and publicized throughout the industry. These deal with:(1) a formatting error in the regional economic data block test file generated by SECPOP2000 for input to MACCS2 which results in MACCS2 misreading the data, (2) an error associated with the formatting of the COUNTY97.DAT economic database file used by SECPOP2000 which result in SECPOP2000 processing incorrect economic and land used data (i.e., missing entries in the Notes column result in data being output for the wrong county), and (3) gaps in the numbered entries in the COUNTY97.DAT economic database file which result in any county beyond county number 955 being handled incorrectly in SECPOP2000. Confirm that all three identified problems were addressed in the SAMA analyses.

5.

Provide the following information with regard to the selection and screening of Phase I SAMA candidates:

a.

Section 3.1.1.1 provides listings of the top 10 basic events based on the risk reduction worth (RRW) for CDF and large early release frequency (LERF). It also states that the basic events were identified with RRWs down to 1.005. However,

the additional events (beyond the top 10) were not provided. Provide the complete listing of the basic events with RRW above the SAMA screening threshold, and identify the related SAMA candidates for each of these basic events.

b.

Section 5.1 briefly discusses the process for SAMA identification but does not elaborate on the process details. From this brief discussion it appears that FENOC utilized both the RRW list and the direct examination of dominant sequences for the purpose of identifying the SAMA candidates. Provide a step-by-step description of the process used for SAMA identification. Include a description of the approach used to identify SAMAs that address external events.

Demonstrate that potential SAMAs were considered for all dominant flood, fire, and seismic event scenarios.

c.

Most of the potential enhancements identified in the IPE and IPEEE have been implemented or addressed by a candidate SAMA. However for a few enhancements the status is unclear. For the following enhancements, indicate if the improvement has been implemented, is no longer being considered and why, and if credit is taken for the improvement in the current PRA. For those enhancements not implemented, indicate their risk significance based on the current version of the PRA and why they should not be considered as Phase II SAMA candidates:

1.

Enhance procedures and training to reduce 4.16 KV breaker failure frequencies (Units 1 and 2).

2.

Locally control and align the component cooling water pumps, and locally control the B train of River Water pump during fire scenarios (Unit 1).

d.

Reference 39, Beaver Valley Power Station ELT 2004 Strategic Plan - Safe Plant Operations was the source of several of potentially risk-beneficial SAMA candidates. However, this document is not discussed in the ER. Provide a copy of this document, or the portions of the document related to identification of potential plant improvements.

e.

Table 6-1 provides a listing of SAMA candidates, their disposition, and the associated screening criteria. However, the basis for screening some SAMA candidates was not clear. Provide additional explanation of why the following SAMAs were screened out.

1.

Unit 1 SAMA 73 - Proceduralize local manual operation of auxiliary feedwater system when control power is lost. Per the NRC Significance Determination Process notebook for Beaver Valley, upon loss of 480 VAC, the auxiliary feedwater valves will remain open and throttling of the valves must be performed locally. Explain why it is stated that there is no need for local manual actions. Provide an assessment of the costs and benefits of potential enhancements to improve operation of the auxiliary feedwater system when control power is lost, including improved Steam Generator (SG) level instrumentation.

2.

Unit 1&2 SAMA 90 - Create a cavity flooding system. The ER indicates that the SAMA intent is met at Unit 1 using existing systems as directed by Severe Accident Management Guidelines (SAMGs), but that the SAMA was screened out at Unit 2 based on excessive cost. Explain this disparity.

6.

Provide the following information with regard to the Phase II cost-benefit evaluations:

a.

SAMA 41 involves primary system depressurization and use of low pressure injection (LPI) when high pressure injection (HPI) has failed. However, it appears to have already been credited in the latest PRA revision. Describe the additional modifications and enhancements that are included in the scope of this SAMA and discuss the basis for the cost estimate.

b.

SAMAs 55, 56, and 165 were considered as alternative approaches for reducing the likelihood of reactor coolant pump (RCP) seal LOCAs. SAMA 55 would eliminate seal LOCAs for all initiators, whereas SAMAs 56 and 165 would eliminate seal LOCAs for all initiators except SBO. The different scopes of these SAMAs do not appear to have been considered in the cost-benefit evaluation since the same cost and benefit values were used for all three SAMAs. Provide either separate cost and benefit estimates for each of these SAMAs, or confirmation that the implementation cost and benefit estimates used to represent these SAMAs are bounding (i.e., the implementation cost is the lowest value and the benefit estimate is the highest value of the three SAMAs).

c.

SAMA 98 involves increasing the containment and core debris cooling following core damage, however, the benefit is estimated based on eliminating containment failures from hydrogen burn. Explain why the benefit of this SAMA would be equivalent to that associated with eliminating hydrogen burns. Also explain why the cost estimate for this SAMA is lower for Unit 1 than for Unit 2.

d.

For SAMAs 112 and 113 the implementation costs appear to be higher than expected. Provide the basis for the cost estimates for these SAMAs.

e.

The benefit of implementing a SAMA is estimated by summing the reductions in four major severe accident costs: offsite exposure cost, off-site economic cost, on-site exposure cost, and on-site economic cost. Table 7-1 provides the reduction in offsite dose and CDF but does not include the reduction in Offsite Economic Cost Risk (OECR). Provide the reduction in OECR for each SAMA.

7.

There are a number of SAMA candidates for which implementation at a single unit would provide the intended benefits at both units, e.g., Unit 1 SAMAs 14, 186, 187, and 188, and Unit 2 SAMAs 14, 186, and 190. Identify all such dual unit SAMAs and describe the development of the implementation cost estimates for these SAMAs.

8.

The following information is needed to clarify that the potential for lower cost SAMA candidates were considered for the following SAMA candidates:

a.

Explain if lower cost alternatives were considered for Unit 1 SAMAs 183 and 184 (which both involve rerouting river water or auxiliary river water pump power and control cables), for example, partially re-routing one train of power cables and

modifying the fire procedure(s) to manually control the river water or the auxiliary river water pump, or using rated fire blankets/barriers rather than rerouting cables.

Verify that no lower cost alternatives are viable.

b.

Explain if lower cost alternatives were considered for Unit 2 SAMAs 179 and 180 (which involve control room and cable tunnel fires, respectively), for example, partially re-routing or protecting one train of service water combined with procedures to allow manual local actions. Verify that no lower cost alternatives are viable.

c.

SAMA 54 (Unit 1), and SAMAs 55, 56, and 165 (Units 1 and 2) are focused on reducing the likelihood of RCP seal LOCAs. However, there could be other lower cost SAMAs such as adding a dedicated self-contained diesel driven pump for seal cooling or cross-connecting the chemical and volume control system (CVCS) from the opposite unit for RCP seal injection. Verify that no lower cost alternatives are viable.