ML070850046

RAI, Revision to Service Water System and Ultimate Heat Sink Temperature Requirements

ML070850046
Person / Time
Site:	Nine Mile Point
Issue date:	03/29/2007
From:	Pickett D NRC/NRR/ADRO/DORL/LPLI-1
To:	O'Connor T Nine Mile Point
david marshall NRR/DORL 415-1547
References
TAC MD4031
Download: ML070850046 (5)

Text

March 29, 2007 Mr. Timothy J. OConnor Vice President Nine Mile Point Nine Mile Point Nuclear Station, LLC P.O. Box 63 Lycoming, NY 13093

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING NINE MILE POINT NUCLEAR STATION, UNIT NO. 2, REVISION TO SERVICE WATER SYSTEM AND ULTIMATE HEAT SINK TEMPERATURE REQUIREMENTS (TAC NO.

MD4031)

Dear Mr. OConnor:

By letter dated January 4, 2007, Nine Mile Point Nuclear Station, LLC requested a revision to Technical Specification (TS) 3.7.1, "Service Water (SW) System and Ultimate Heat Sink (UHS), for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2). The proposed TS revision would: revise the existing Limiting Condition for Operation statement to require four operable SW pumps to be in operation when SW subsystem supply header water temperature is # 82 °F; add a requirement that five operable SW pumps be in operation when SW subsystem supply header water temperature is > 82 °F and #84 °F; delete Condition G and the associated Required Actions and Completion Times; revise Surveillance Requirement 3.7.1.3 to increase the maximum allowed SW subsystem supply header water temperature from 82 °F to 84 °F; and modify the requirements for increasing the surveillance frequency as the temperature approaches the limit.

The Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in that letter and has determined that additional information is needed to complete its review.

Enclosed is the NRC staffs request for additional information (RAI). The RAI was discussed with your staff on March 21, 2007, and it was agreed that your response would be provided within 30 days from the date of this letter.

Sincerely,

/RA/

Douglas V. Pickett, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-410

Enclosure:

RAI cc w/encl: See next page

March 29, 2007 Mr. Timothy J. OConnor Vice President Nine Mile Point Nine Mile Point Nuclear Station, LLC P.O. Box 63 Lycoming, NY 13093

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING NINE MILE POINT NUCLEAR STATION, UNIT NO. 2, REVISION TO SERVICE WATER SYSTEM AND ULTIMATE HEAT SINK TEMPERATURE REQUIREMENTS (TAC NO.

MD4031)

Dear Mr. OConnor:

By letter dated January 4, 2007, Nine Mile Point Nuclear Station, LLC requested a revision to Technical Specification (TS) 3.7.1, "Service Water (SW) System and Ultimate Heat Sink (UHS), for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2). The proposed TS change would: revise the existing Limiting Condition for Operation statement to require four operable SW pumps to be in operation when SW subsystem supply header water temperature is # 82 °F; add a requirement that five operable SW pumps be in operation when SW subsystem supply header water temperature is > 82 °F and #84 °F; delete Condition G and the associated Required Actions and Completion Times; revise Surveillance Requirement 3.7.1.3 to increase the maximum allowed SW subsystem supply header water temperature from 82 °F to 84 °F; and modify the requirements for increasing the surveillance frequency as the temperature approaches the limit.

The Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in that letter and has determined that additional information is needed to complete its review.

Enclosed is the NRC staffs request for additional information (RAI). The RAI was discussed with your staff on March 21, 2007, and it was agreed that your response would be provided within 30 days from the date of this letter.

Sincerely,

/RA/

Douglas V. Pickett, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-410

Enclosure:

RAI cc w/encl: See next page DISTRIBUTION:

PUBLIC RidsNrrPMDPickett RidsNrrLASLittle MDavid LPLI-1 PDI-1 Reading File RidsNrrDssSbpb RidsOgcRp RidsNrrDssScvb RidsNrrAcrsAcnwMailCenter Accession Number: ML070850046 NRR-088 OFFICE LPL1-1/PE LPL1-1/PM LPL1-1/LA SBPB/BC SCVB/BC LPL1-1/BC(A)

NAME MDavid DPickett SLittle JSegala RDennig JBoska DATE 3/29/07 3/29/07 3/29/07 03 /12 /07 03 /13 /07 3/29/07 OFFICIAL RECORD COPY

Nine Mile Point Nuclear Station cc:

Mr. Michael J. Wallace Washington, DC 20006 President Nine Mile Point Nuclear Station, LLC Supervisor c/o Constellation Energy Group Town of Scriba 750 East Pratt Street Route 8, Box 382 Baltimore, MD 21202 Oswego, NY 13126 Mr. Mike Heffley Carey W. Fleming, Esquire Senior Vice President and Chief Senior Counsel Nuclear Officer Constellation Generation Group, LLC Constellation Generation Group 750 East Pratt Street, 17th Floor 1997 Annapolis Exchange Parkway Baltimore, MD 21202 Suite 500 Annapolis, MD 21401 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 126 Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Mr. Paul D. Eddy Electric Division NYS Department of Public Service Agency Building 3 Empire State Plaza Albany, NY 12223 Mr. Peter R. Smith, President New York State Energy, Research, and Development Authority 17 Columbia Circle Albany, NY 12203-6399 Mark J. Wetterhahn, Esquire Winston & Strawn 1700 K Street, NW

REQUEST FOR ADDITIONAL INFORMATION NINE MILE POINT NUCLEAR STATION, UNIT NO. 2 REVISION TO SERVICE WATER SYSTEM AND ULTIMATE HEAT SINK TEMPERATURE REQUIREMENTS The Nuclear Regulatory Commission (NRC) staff has performed its initial review of your January 4, 2007, request to revise Technical Specification (TS) 3.7.1, "Service Water (SW)

System and Ultimate Heat Sink (UHS), for Nine Mile Point Nuclear Station, Unit No. 2 (NMP2).

As a result of that review, we have determined that additional information is required to adequately evaluate the acceptability of the proposed change.

1. In Section 4.2.1.3 of the request, it states, "The long-term post-LOCA [loss-of-coolant accident] drywell temperature profile would be several degrees higher because of the impact of the higher UHS temperature on RHR [residual heat removal] heat exchanger heat removal capacity." Provide information on the post-LOCA temperature profile and equipment qualification profile and safety margin between the two temperature profiles.

Explain what actions are to be taken to maintain drywell temperature within a limit that can ensure the validity of the equipment qualification temperatures previously approved.

2. There is no information in the request regarding which computer code was used to analyze the thermal and hydraulic performance of the RHR heat exchangers or whether it was updated. Provide information on the computer code used for the analysis and accuracy of the analysis compared with other recognized calculation methods.

3. In Section 4.2.1.4 of the request, it states, "Post-LOCA suppression pool cooling is provided by the RHR system, which is cooled by the SW system. The calculated peak post-LOCA suppression pool water temperature for power uprate conditions (rated thermal power of 3,467 MWt) is approximately 4 °F below the 212 °F design limit. This analysis was based on a UHS temperature of 82 °F and also assumed that 5 percent of the RHR heat exchanger tubes are plugged." Justify that the peak suppression pool temperature design limit would not be exceeded for a LOCA with the UHS temperature continuously at 84 °F. Please validate it with a computer analysis.

4. In Section 4.1.2.2 of the request, it states, "The three RBCLC [reactor building closed loop cooling] system heat exchangers are cooled by the SW system." Provide information on the impact of increased SW temperature on the RBCLC system inside the drywell. Explain whether the cooling water system that is cooled by degraded UHS conditions can maintain equipment operability inside the drywell.

5. The reactor building closed loop cooling system is used post-LOCA to provide longer term cooling water for the control room chillers, spent fuel pool system, and instrument air compressors. Provide information on how these systems and components are to be affected by the degraded ultimate heat sinks.

6. In Section 4.2.1.1 of the request, it states, The differential temperature between the 84 °F SW and the TS-required pool temperature limit is adequate to ensure that the Enclosure

suppression pool can be maintained within the TS-required temperature limits; therefore, the accident analysis initial condition is not affected.

Per TS 3.6.2.1, "Suppression Pool average Temperature," Limiting Condition for Operation (LCO) 3.6.2.1 a., which is applicable to reactor operating modes 1, 2 and 3, suppression pool average temperature shall be "#90 °F with THERMAL POWER > 1%

RTP [Rated Thermal Power] and no testing that adds heat to the suppression pool is being performed; If the average temperature of the suppression pool is > 90 °F and #110 °F, the required action for this LCO is that the pool average temperature should be restored to #90 °F within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, otherwise the reactor thermal power should be reduced to #1% RTP within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Please confirm that analysis was performed to verify that with a SW temperature of 84 °F, the RHR system heat exchanger can bring the suppression pool temperature at or below its TS limit of 90 °F from 110 °F within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Please provide the time duration for which the one RHR heat exchanger has to operate to bring the suppression pool temperature to 90 °F using 84 °F SW temperature and 82 °F SW temperature, starting from the same initial suppression pool temperature of 110 °F, and with the design basis heat exchanger tube plugging and fouling factor.

7. NMP2 Updated Safety Analysis Report Table 6.2-9 specifies an initial drywell temperature of 135 °F used for LOCA containment response analysis. Please confirm that analysis was done to verify that with the SW temperature of 84 °F, assuming design basis tube plugging and fouling factors for the RBCLC water heat exchangers and drywell coolers, the drywell can be maintained at or below 135 °F during normal plant operation. If the analysis shows that the drywell temperature exceeds 135 °F, what is the impact on LOCA maximum drywell pressure and steam line break maximum drywell temperature?

8. In Section 4.3.1 of the request, the third sentence states, The peak suppression pool temperature corresponding to an 84 °F UHS temperature has been evaluated and found to be within the ATWS [anticipated transient without scram] pool temperature limit of 190 °F. What was the peak suppression pool temperature calculated in the evaluation and how was it calculated?