ML20198F999
| ML20198F999 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 12/04/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198F989 | List: |
| References | |
| IEB-96-003, IEB-96-3, NUDOCS 9812280268 | |
| Download: ML20198F999 (4) | |
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2066H001
- * * * * ,o ASSESSMENT OF LICENSING BASIS FOR USE OF CONTAINMENT OVERPRES'SURE CREDIT FOR NET POSITIVE SUCTION HEAD ANALYSES POWER AUTHORITY OF THE STATE OF NEW YORK JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333
1.0 BACKGROUND
By [[letter::JAFP-98-0306, Forwards Response to NRC Resulting from ECCS Suction Strainer 980521 Meeting,Per NRC Bulletin 96-003.Addl Encls Contain SEs for RHR & Core Spray Systems Suction Strainer Replacements,Revised Calculation & Commitments|letter dated September 16,1998]] (Reference 1), the Power Authority of the State of New York (the licensee, also known as the New York Power Authority) provided information regarding NRC Bulletin (B) 96-03," Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors"(Reference 2) for the James A. FitzPatrick Nuclear Power Plant. This information addressed issues discussed in a May 21,1998, meeting between the NRC staff and NYPA personnel, as documented in a meeting summary dated June 4,1998 (Reference 3). One of the issues discussed at this meeting was FitzPatrick's current licensing basis for the use of containment overpressure to ensure adequate net positive suction head (NPSH) to the emergency core cooling system (ECCS) pumps.
In its letter, the licensee stated that the conclusion that FitzPatrick is operating within its licensing basis related to the issue of containment overpressure for the ECCS pumps. This conclusion was based on the original Atomic Energy Commission (Aw ^ '-ty Evaluation Report (SER) which noted that the FitzPatrick did not fully meet the gaelines of Sa'ety Guide l- 1 (Reference 4). The NRC staff has determined that it agrees with NYPA that FitzPatrick is l within its licensing basis since they have shown that the AEC SER (Reference 5) had mista!:enly described the containmer.s overpressure time period as 25 minutes instead of 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> as shown in the licensee's submittal. However, it does not appear that this mistake was corrected by the licensee or the staff until this time, j 2.0 plSCUSSION l
l In the original AEC SER dated November 20,1972, the staff made the following conclusion i l
with regards to adequate NPSH for the ECCS pumps: ;
The applicant analyzed the availability of adequate net positive suction head (NPSH) for ;
allECCS pumps in conformance with Safety Guide No.1 which requires that there be no reliance on calculatedincreases in containment pressure. The most limiting case occurs during the long term transient following the design basis LOCA when one core spray and l
one RHR pump will be running continuously. The analysis shows that a containment l
9812280268 981~.04 PDR ADOCK 05000333 0 PDR Enclosure
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- i overpressure ofless than 2 psi would be required fora period of about 25 minutes during the transient to assure adequate NPSH. A containment overpressure of 7 psiis available 1 i
during this period. Although the design does not fully meet the guidelines of the safety guide we have concluded that the applicant's analysis is conservative and that there l
, should be adequate NPSH to the ECCS pumps even in the unlikely event of a LOCA. l l y 7<
l As described in the AEC SER, the staff found the small amount of containment overpressure, l
less than 2 psi, that Fi+.zPatrick was crediting for the' residual heat removal (RHR) pumps acceptable based on the analysis presented in Supplemen(4 (Reference 6) to the FitzPatrick i Final Safety Analysis Report (FSAR). FSAlf Supplement 4' responded to question 6.4 from the l staff which requested the 'icensee to sppw the margin in required NPSH (NPSHR) in terms of overpressure and the time that will be ayallable to th.e_ core standby cooling system pumps for the various amounts of equipment assunWd.to be ope'rable. The analysis provided in Supplement 4 was based on a maximurri'shpre'ssion pool temperature of 205 degrees Fahrenheit and a maximum service water teinperature of 77 degrees Fahrenheit. However, the actual results of the analysis were provided in graphical form. Supplement 4 provided the following information:
The most limiting of all the various mo[es5ccurs during the long term transient following a design basis loss of coolant accrdenthvhen one core spray and one RHR pump will be running continuously. Figure Q.6.4.1 is a plot of both the minimum containment pressure required in order that the RHR purbps (Mbst limiting) has adequate NPSH and a plot of the minimum containment pressuQ that svould actually occur. Except for the long term
adequate NPSH. E l The staff notes that Figure Q.6.4-1 pd@e[t'hle NPSHR for the RHR pumps starting at time l greater than 10 seconds, i.e., short terrngequifgnents were not evaluated. As shown on the l figure, the time period considered in this analysip was between 10 to 108 seconds post loss-l of-coolant accident. The actual points on_Figur,e Q.6.4-1 vyhere the requirement for containment overpressure begins and ends was not discussed by the AEC nor the licensee in their Supplement 4 submittal. In their Septegnber.16,1998, submittal, the licensee stated that based on Figure Q.6.4-1 the requirement toy:redit containpent overpressure begins at l approximately 34,000 seconds (0.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) and ends at approximately 130,000 seconds (36.1 l hours) for a total of 26.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. While the spect. points of initial and final containment overpressure required time periods is openfor interpretation, it is clear that the AEC SER mistakenly stated 25 minutes instead of 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />. Therefore, the staff concludes that FitzPatrick was licensed to credit less than 2 pn Mr the RHR pumps for the time period depicted on Figure O.6.4-1.
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According to the FitzPatrick Generic Letter (GL) 97-04 resp.onse (References 7 and 8), the current containment overpressure credit required is 1.97 psi for the RHR pumps and 1.75 psi for the core spray pumps at the maxinium suppression pool temperature of 213 'F. These
, values are based on plant operation at 2563 MWt (uprated power) and a maximum lake j temperature of 85 *F. The licensee stated that 'the increase in power level was approved at a
- lake temperature of 82 'F and took credit for up to 2 psig torus overpressurization for both the j CS and LPCI (RHR) pumps." Amendment 239 to the Technical Specifications changed the j maximum lake temperature to 85 degrees Fahrenheit while still relying on less than 2 psig of l
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l containment overpressure to ensure adequate NPSH. Although it is not evident that the staff did an actual review of the NPSH calculations for the power uprate and Amendment 239, the staff believas that the current design basis of crediting less than 2 psig of containment overpressure for the RHR and core spray pumps is consistent with the FitzPatrick licensing basis.
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! Based on the above discussion, the staff has concluded that FitzPatrick remains within their licensing basis with respect to the amount of containment overpressure credited for the lorg term analyses of NPSH for the RHR and core spray pumps. Specifically, the staff believes that when FitzPatrick was licensed, it was licensed to credit less than 2 psig of containment overpressure for the RHR for the time period presented in Figure Q.6.4-1 of Supplement 4 of the FitzPatrick FSAR. Additionally, staff approval of power uprate and Amendment 239 of the FitzPatrick Technical Specifications allowed credit of less than 2 psig of containment overpressure for the core spray pumps. Based on this review, the staff believes that the current design basis of crediting less than 2 psig of containment overpressure for the RHR and core spray pumps is consistent with the FitzPatrick licensing basis.
Conclusion i The staff has reviewed FitzPatrick's September 16,1998, and GL 97-04 responses. The staff l
' agrees with the licensee that FitzPatrick is within its licensing basis since the licensee has shown that the AEC SER had mistakenly described the containment overpressure time period as 25 minutes instead of 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> as shown in the FitzPatrick Supplement 4 response. '
Additionally, the staff concludes that the cur *ent use of containment overpressure credit of less than 2 psig for the RHR and core spray pumps is consistent with the FitzPatrick licensing basis due to staff approval of power uprate and Amendment 239 of the FitzPatrick Technical Specifications. The staff notes that it would consider any future increase in reliance of containment overpressure credit, above 2 psig, for the RHR and/or core spray pumps to be an unreviewed safety question, which would require NRC approval to amend the operating license before the licensee could make such a change. This would also include any increase or change in time the containment overpressure is required, i.e., a longer period than currently depicted in the GL 97-04 response figures and as described in FSAR Section 6.5.1, or short-term requirements.
Principal Contributor. K. Kavanagh Date:
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References 1.
Colomb, M.J., NYPA, to USNRC, " James A. FitzPatrick Nuclear Power Plant Docket No.
' 50-333 - Information Regarding NRC Bulletin 96 Potential Plugging of ECCS Suction Strainers," September 16,1998.
2.
USNRC Bulletin 96-03, " Potential Plugging of Emergency Core Cooling Suction Strainers By Debris in Boiling-Water Reactors," May 6,1996. I 3.
- Meeting Summary of May 21,1998, Regarding Emergency Core Ccoling Suction Strainer Modifications (TAC No. M96146)," June 4,1998.
! 4.
USNRC Safety Guide 1, " Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal System Pumps," November 2,1970.
5.
US Atomic Energy Commission," Safety Evaluation of James A. FitzPatrick Nuclear Power Plant," November 20,1972.
i 6.
NYPA to US Atomic Energy Commission, " Supplement 4 to the FitzPatrick Final Safety Analysis Report," February 9,1972.
- 7. USNRC Generic Letter 97-04, " Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps," October 7,1997.
8.
Knubel, J., NYPA. to USNRC, " Indian Point 3 Nuclear Power Plant Docket No. 50-286, James A. FitzPatrick Nucleur Power Plant Docket No. 50-333,90-day Response to NRC Generic Letter 97-04 Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps," December 23,1997.
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