SBK-L-11125, Supplement to Response to Request for Additional Information - April 18, 2011, License Renewal Application

Supplement to Response to Request for Additional Information - April 18, 2011, License Renewal Application

ML11166A255
Person / Time
Site:	Seabrook
Issue date:	06/10/2011
From:	Freeman P NextEra Energy Seabrook
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-11125
Download: ML11166A255 (6)

Text

NEXTera ENERGY June 10, 2011 SBK-L-1 1125 Docket No. 50-443 U.S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 Seabrook Station Supplement to Response to Request for Additional Information - April 18, 2011 NextEra Energy Seabrook License Renewal Application

References:

1.. NextEra Energy Seabrook, LLC letter SBK-L-10077, "Seabrook Station Application for Renewed Operating License," May 25, 2010. (Accession Number ML101590099)

2. NRC Letter "Schedule Revision and Request for Additional Information for the Review of the Seabrook Station License Renewal Application Environmental Review (TAC Number ME3959) March 4, 2011. (Accession Number MLl 10590638)

3. NextEra Energy Seabrook, LLC letter SBK-L- 11067, "Seabrook Station Response to Request for Additional Information, NextEra Energy Seabrook License Renewal Application," April 18, 2011. (Accession Number MLl 122A075)

In Reference 1, NextEra Energy Seabrook, LLC (NextEra) submitted an application for a renewed facility operating license for Seabrook Station Unit 1 in accordance with the Code of Federal Regulations, Title 10, Parts 50, 51, and 54.

In Reference 2, the NRC requested additional information in order to complete its review of the License Renewal Application. In Reference 3, NextEra submitted its responses to the staffs RAIs.

In a discussion with the Staff, NextEra Energy Seabrook was requested to supplement the previous response for clarity. The requested information is enclosed.

NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874

United States Nuclear Regulatory Commission SBK-L- 11125 / Page 2 The License Renewal Application, Appendix E, page F-6 contains a list of acronyms used in these responses. If there are any questions or additional information is needed, please contact Mr. Richard R. Cliche, License Renewal Project Manager, at (603) 773-7003.

If you have any questions regarding this correspondence, please contact Mr. Michael O'Keefe, Licensing Manager, at (603) 773-7745.

Sincerely, NextEra Energy Seabrook, LLC.

Paul 0. Freeman Site Vice President Enclosure cc:

W.M. Dean, NRC Region I Administrator G. E. Miller, NRC Project Manager, Project Directorate 1-2 W. J. Raymond, NRC Resident Inspector R. A. Plasse Jr., NRC Project Manager, License Renewal M. Wentzel, NRC Project Manager, License Renewal Mr. Christopher M. Pope Director Homeland Security and Emergency Management New Hampshire Department of Safety Division of Homeland Security and Emergency Management Bureau of Emergency Management 33 Hazen Drive Concord, NH 03305 John Giarrusso, Jr., Nuclear Preparedness Manager The Commonwealth of Massachusetts Emergency Management Agency 400 Worcester Road Framingham, MA 01702-5399

United States Nuclear Regulatory Commission SBK-L-11125 / Page 3 NEXTera I, Paul 0. Freeman, Site Vice President of NextEra Energy Seabrook, LLC hereby affirm that the information and statements contained within are based on facts and circumstances which are true and accurate to the best of my knowledge and belief.

Sworn and Subscribed Before me this

/0 day of ,2011 Paul 0. Freeman Site Vice President Notary Pub ic

Enclosure to SBK-L-11125 NextEra Energy Seabrook Supplement to Response to Request for Additional Information - April 18, 2011 Regarding Severe Accident Mitigation Alternatives Analysis

NextEra Energv Supplement to Response to RAI - April 18. 2011 In a discussion with the Staff regarding the cost estimates for SAMA Cases 25, 26, and 39 provided in NextEra Energy Seabrook response dated April 18, 2011 (Reference 3), it was determined that the evaluation section for these three SAMA Cases in Table X SAMA Sensitivity Evaluation Using Seismic Risk Multiplier of 2.1 supported an increase in the cost estimates provided in the table. The previous sensitivity evaluation for each SAMA case in Table X-2 provided a determination that the cost estimate was based on a conservative (low) estimate. Enclosed is a revised Table X-2 for SAMA cases 25, 26 and 39 which reflects a revised cost estimate for these SAMAs. The revised cost estimates for these SAMAs are still within the range of previously provided industry cost estimates.

The changes to the previous SAMA Cases are shown in the following Table with the change highlighted by strikethroughs for deleted text and bolded italics for inserted text.

Table X-2 Seabrook Station Sensitivity Evaluation using Seismic Risk Multiplier of 2.1 (SAMA Candidates are from Seabrook ER Table F.8-1)

Nominal Upper Seabrook SAA PoetilBound Cost SAMA Povent Discussion Numer Impovmen PRA Case Benefit at 2Ix Bene at Benefit a Est Estimate Evaluation e2.Ix 2.Ix Not cost beneficial. PRA case LOCA02 conservatively assumes guaranteed success of all high head and intermediate head injection pumps (charging and SI pumps.) Therefore, the benefit of installing a single, independent, backup injection system is judged conservatively high. Installation of an independent, active or passive injection system is judged not practical and cost is expected to significantly exceed the Install an conservative benefit. Given the seismic ruggedness of the existing injection system(s), any independent Improved >$5M new/additional system would need to be equally rugged to significantly reduce plant risk. Including 25 active or passive prevention of core LOCA02 $978K $1.9M >VM seismic ruggedness in the design would further increase cost.

high pressure melt sequences This improvement was previously estimated at greater than $2 million dollars in the Pilgrim License injection system Renewal application. In the Duane Arnold License Renewal application, the Pilgrim estimate was judged to be low and used a $20 million estimate based on similar modification experience. Given these industry estimates and basedon the Seabrook plant design, the costfor SAMA implementation would be -epectedto be in the range of S5M to $IOM or tore- These Both estimates significantly exceed the upper bound sensitivity benefit ofr$1.9M, and a no more refined estimate is not warranted.

Not cost beneficial. PRA case LOCA02 conservatively assumes guaranteed success of all high head and intermediate head injection pumps (charging and SI pumps.) Therefore, the benefit of installing a single, independent, backup injection system is conservatively high. Installation of an additional injection system is judged not practical and cost is expected to significantly exceed the conservative benefit. Given the Provide an seismic ruggedness of the existing injection system, any new/additional system would need to be equally additional high Reduced frequency >$5M rugged to significantly reduce plant risk. Including seismic ruggedness in the design would further of core melt from LOCA02 $978K $1.9M >$2M increase cost.

26 pressure injection pump with small LOCA and This modification was assumed to be the equivalent of adding one new high pressure injection pump independent SBO sequences powered by a diesel rather than an electric motor with a suitable injection path and suction source. In the diesel Duane Arnold License Renewal application, the cost of this was one half the cost of replacing pumps discussed in SAMA 25 above, the cost would be $10 million. Given the industry estimate and basedon the Seabrook plant design, the costfor SAMA implementation would be expected to be in the range of

$5A1 to $10M. These T4is estimates significantly fahexceeds the upper bound sensitivity benefit of

$1.9M and a no more refined cost estimate is not warranted.

Not cost beneficial. PRA case LOCA02 conservatively assumes guaranteed success of all high head and intermediate head injection pumps (charging and SI pumps.) Therefore, the benefit of replacing two electric motor pumps with diesel-driven pumps is conservatively high. Installation of diesel-driven pumps Reduced common in place of the existing motor-driven pumps is judged not practical and cost is expected to significantly f

cause failure of the exceed the conservative benefit. Given the seismic ruggedness of the existing injection system, any Replace two of safety injection the new/additional equipment would need to be equally rugged so as to not impact the current seismic design the four electric 39 sfetyinjetion ysae.T The system. injet>5M intent basis. Including seismic ruggedness in the design would further increase cost.

sftpumps with of this SAMA is to LOCA02 $978K $1.9M >$2M Changes to how safety related pumps are powered would require substantial changes to the foot print of diesel-powered provide diversity the system and re-analysis of safety related piping in addition to the procurement and installation of the dies within the high- and diesel power device. Due to complexity of this modification, the Duane Arnold License Renewal pumps low-pressure safety application estimates the cost to be similar in nature to replacement of pumps mentioned in SAMA 25 injections systems above ($20 million). Given these industryestimates and based on the Seabrookplant design, the cost for SAMA implementation would be expected to be in the range of $SM to $10M. As this cost range value substantially exceeds the upper bound sensitivity benefit of $1.9M, a no more refined estimate is not warranted.