ML070100148

Draft RAI

ML070100148
Person / Time
Site:	Salem
Issue date:	01/08/2007
From:	Richard Ennis NRC/NRR/ADRO/DORL/LPLI-2
To:	Chernoff H NRC/NRR/ADRO/DORL/LPLI-2
Ennis R
References
TAC MD2740, TAC MD2741
Download: ML070100148 (3)

Text

January 8, 2007 MEMORANDUM TO: Harold K. Chernoff, Chief, Section 2 Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: Richard B. Ennis, Senior Project Manager /RA/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

SALEM NUCLEAR GENERATING STATION, UNIT NOS. 1 AND 2, DRAFT REQUEST FOR ADDITIONAL INFORMATION (TAC NOS. MD2740 AND MD 2741)

The attached draft request for information (RAI) was transmitted on January 8, 2007, to Mr. Jamie Mallon of PSEG Nuclear LLC (the licensee). This information was transmitted to facilitate an upcoming conference call in order to clarify the licensees amendment request for Salem Nuclear Generating Station, Unit Nos. 1 and 2, dated August 4, 2006. The proposed amendment would revise the Technical Specifications to allow the movement of irradiated fuel inside containment to commence at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after shutdown or at the decay time calculated using the licensees spent fuel pool integrated decay heat management program, whichever is later.

This memorandum and the attachment do not convey or represent an NRC staff position regarding the licensee's request.

Docket Nos. 50-272 and 50-311

Attachment:

Draft RAI

January 8, 2007 MEMORANDUM TO: Harold K. Chernoff, Chief, Section 2 Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: Richard B. Ennis, Senior Project Manager /RA/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

SALEM NUCLEAR GENERATING STATION, UNIT NOS. 1 AND 2, DRAFT REQUEST FOR ADDITIONAL INFORMATION (TAC NOS. MD2740 AND MD 2741)

The attached draft request for information (RAI) was transmitted on January 8, 2007, to Mr. Jamie Mallon of PSEG Nuclear LLC (the licensee). This information was transmitted to facilitate an upcoming conference call in order to clarify the licensees amendment request for Salem Nuclear Generating Station, Unit Nos. 1 and 2, dated August 4, 2006. The proposed amendment would revise the Technical Specifications to allow the movement of irradiated fuel inside containment to commence at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after shutdown or at the decay time calculated using the licensees spent fuel pool integrated decay heat management program, whichever is later.

This memorandum and the attachment do not convey or represent an NRC staff position regarding the licensee's request.

Docket Nos. 50-272 and 50-311

Attachment:

Draft RAI DISTRIBUTION PUBLIC RidsNrrDorlLpl1-2 JSegala LBenton PDI-2 Reading RidsNrrPMREnnis GPurciarello PHearn RidsNrrDorlDpr RidsNrrPMSBailey ACCESSION NO.: ML070100148 OFFICE PDI-2/PM NAME REnnis DATE 1/08/07 OFFICIAL RECORD COPY

DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED LICENSE AMENDMENT REFUELING OPERATIONS - DECAY TIME SALEM NUCLEAR GENERATING STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-272 AND 50-311 By letter dated August 4, 2006, PSEG Nuclear LLC (the licensee) submitted an amendment request for Salem Nuclear Generating Station, Unit Nos. 1 and 2 (Salem). The proposed amendment would revise the Technical Specifications (TSs) to allow the movement of irradiated fuel inside containment to commence at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after shutdown or at the decay time calculated using the licensees spent fuel pool (SFP) integrated decay heat management (IDHM) program, whichever is later.

The Nuclear Regulatory Commission (NRC) staff has reviewed the information the licensee provided that supports the proposed amendment and would like to discuss the following issues to clarify the submittal.

Background to your letter dated August 4, 2006 (Calculation S-C-SF-MEE-1679, Revision 1),

evaluates the cooling capability of the spent fuel pool cooling system (SFPCS). Section 4.1 of to your letter states, The evaluation (Attachment 5) demonstrates that a fully radiated 193 element reactor core can be off-loaded to either Salem spent fuel pool with 85-hours of in vessel decay provided the CCW [component cooling water] outlet temperature is less than or equal 71°F. The NRC staff review noted the following issues in review of the calculation regarding whether an 85-hour delay time is conservative for the conditions stated:

a) Tables 3 and 4 of the calculation show switching of SFCS heat exchanger alignment many times at various and predictable time intervals to remove decay heat after full core offload. In Table 3 for normal two heat exchanger operations, the SFCS is switched from normal operation to parallel heat exchanger operation back and forth to maintain both SPFs below 149°F. In Table 4 for one heat exchanger operation, the SFCS is switched from cross-connect heat exchanger operation on one SFP to normal operations on the other SFP back and forth to maintain both SFPs below 180°F. The Time to Switch HX time intervals early in the sequences shown in Tables 3 and 4 seem short, especially in Table 4.

Considering the time required to change the SFP cooling alignment, the NRC staff is concerned whether the heat exchanger switching operations can be performed as listed in Tables 3 and 4 per procedures without exceeding SFP temperature limits of 149°F and 180°F as specified in the Updated Final Safety Analysis Report (UFSAR).

b) Where referring to the stated conservatisms of the calculation, Section 4.1 of Attachment 1 to your letter states, These inherent conservatisms are of sufficient magnitude to account for any foreseeable changes in river water temperature or other non-conservative assumptions. The NRC staff raises the following concerns regarding this statement:

1) From Figure 9.1-5 of the UFSAR, it appears that there would not be appreciable natural circulation cooling from the reactor vessel to the SFP while residual heat removal cooling of the reactor vessel with all the fuel elements removed.

2) Section 4.1 of Attachment 1 (itemized conservatism 1) states, in part, that:

Consequently, if the pool reaches 180°F, evaporative cooling plus makeup heating removes approximately 9% of the peak heat This does not seem to be a conservatism because, as is stated in your letter and the calculation, evaporative cooling is considered in the one heat exchanger case.

3) Calculation S-C-SF-MEE-1679 computes bulk SFP temperature (assumes instantaneous mixing) and computes heat exchanger switching operations and minimum decay time using the UFSAR temperature limits of 149°F and 180°F.

If SFP temperature gradients exist, this does not seem conservative.

4) Calculation S-C-SF-MEE-1679, Revision 1, takes credit for the volume of the transfer pool. Revision 0 did not take credit for the transfer pool. Adding the transfer pool increases the available heat capacity by more than 50% per Section 3.2.14 of the calculation. It is questionable whether crediting the volume of the transfer pool in a calculation that uses bulk temperature (instantaneous mixing) while using the UFSAR temperature limits of 149°F and 180°F is conservative.

Questions Based on the above issues, the NRC staff requests the following additional information:

1) When determining the minimum decay time, how does the IDHM program account for the time needed to switch the heat exchanger alignment of the SFP cooling system back and forth similar to what is required in Calculation S-C-SF-MEE-1679, Revision 1?

2) How much time do the operators need to align the SFCS for the various configurations required in Tables 3 and 4 of Calculation S-C-SF-MEE-1679, Revision 1?

3) The Time to Switch HX column in both Tables 3 and 4 of calculation S-C-SF-MEE-1679, Revision 1 appears to be dependent on the Tube Flow values in Table 2, which are 2500 gallons per minute (gpm) and 1500 gpm. How accurate are these two flow rates as compared to actual SFPCS flow rates? Does the IDHM use actual SFPCS flow as determined by either actual measurement or by a flow model?

4) The amendment request proposes to revise TS Limiting Condition for Operation (LCO) 3.9.3 to reference the IDHM program as the means to determine the LCO decay time. Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(c)(5) requires, in part, that the TSs contain administrative controls relating to procedures necessary to assure operation of the facility in a safe manner. Consistent with these requirements, the IDHM program should be added to TS Section 6.0, Administrative Controls. Please submit your IDHM program for review and revise TS Section 6.0 accordingly.