ML20206D855
| ML20206D855 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/14/1988 |
| From: | Wambach T Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20206D851 | List: |
| References | |
| NUDOCS 8811170304 | |
| Download: ML20206D855 (5) | |
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- g UNITED STATES a
g NUCLEAR REGULATORY COMMISSION L
'l WASHINGTON, D. C. 20555
'g.... g SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 117 TO PROVISIONAL OPERATING LICENSE NO. D CONSUMERS POWER COMPANY PALISADES PLANT
_ DOCKET NO. 50-255
1.0 INTRODUCTION
Consuners Power Company (the licensee) made application for an amendment to the Provisional Operating License (OPR-20) for Palisades Plant on December 22, 1987, to revise the Technical Specification requirements for low temperature overpressure protection (LTOP).
The LTOP provides relief capability to protect the reactor vessel from the potential for brittle fracture.
The heatup and cooldown limits in the Technical Specifications reflect the temperature and pressure limits calculated according to the requirements of Appendix G to 10 CFR Part 50, using the methods in Regulatory Guide 1.99, Revision 2.
These limits were last revised by Amendment 97 to the Palisades Operating License issued on August 21, 1986.
The relief valve settings of LTOP most then be appropriately lowered to prctect against violating the new limits.
Additional restrictions were required during heatup and cooldown because of the limited capacity of the LTOP relid valves.
As part of these requirements, the high pressure safety injection (HPSI) pumps were to be randered inoperable at primary coolant system temperatures less than 430'F.
Preliminary review by the NRC staff raised a concern about the lack of protection for a loss of coolant accident (LOCA) at such an elevated temperature and pressure in the primary coolant system.
The licensee responded to telephonic inquiries from the NRC staff by letters dated January 20 and 22, 1988.
In these letters, the licensee committed to revised requirements that maintain one HPSI pump operable above 350'F.
By application dated April 12, 1988, the licensee submitted a revised amendment request to incorporate changes to the Technical Specifications that conform to the commitmants made in the January 20 and 22, 1988 letters.
In addition, changes in the allowable heatup and cooldown rates, as well as the pressure-temperature limits for heatup, coo!down,and hydrostatic testing, were proposed in the April 12, 1988 application.
2.0 EVALUATION The basis for the existing heatup and cooldown curves in the Palisades Technical Specifications is discussed in the NRC's Safety Evaluation issued with Amendment 97 to the Palisades Operating License.
The NRC staff had done an independent calculation and concluded that:
"The family of heat-up b$k$$bb
.c 2-and cool-down curves (0'F/hr through 100'F/hr) computed by the licensee 4
1 either conservatively bound the values calculated by the staff or differ by 2% or less." In the January 20, 1988 letter, the licensee informed the NRC that in performing the calculations for heatup limits, the licensee had i
i included a temperature term into the stress intensity calculations for both I
the 1/4T and 3/4T flaw locations in the beltline wali (1/4T and 3/4T indicate 1/4 vescel wall thickness and 3/4 vessel wall thickness from the inside surface of the vessel).
Their inclusion of this temperature term i
for the 1/4T location is unnecessary e d considered an oversight because the 1/47 location experiences compression ra+.her than tension.
The NRC staff calculation did not include this term in the 1/4T calculation.
The licensee's April 12, 1988 revision to the application provided new curves that were corrected to remove this error.
The resulting heatup curves are censistent with the NRC staff results supporting Amendment 97, within the calculational accuracy of the methodology (approximately 2 percent).
The NRC staff, thcrefore, continues to find that the proposed pressure-temperature limits meet the safety margins of Appendix G, 10 CFR Pag /cm 50,2 (E > 1MeV) and may be incorporated into the plant's Technical for 9 effective full power years based on a fluence of 1.8 x 10 n j
Specifications.
~
To reduce the potential for exceeding the Appendix G limits while i
maintaining adequate makeup capability in the event of loss of primary coolant, additional restrictions have been added to the Technical Specifications.
These include: 1) a primary coolant pump shall not be started unless the secondary system temperature is less than or equal to the primary system cold leg temperature unless the primary system cold leg temperature is greater than or equal to 450'F; 2) the heatup and cooldown rates are limited to prescribed values dependent upon the primary coolant i
system cold leg temperature; 3) pressurizer heatup and cooldown rates are prescribed; 4) relief valve settings for LTOP are prescribed dependent upon primary coolant system cold leg temperatures; 5) allowance is made for relief valve inoperability*provided the primary coolant system cold leg temperature is greater than 385 F, a bubble is formed in the pressurizer and pressurizer 1
level is less than 60 percent; 6) operability of the HPSI pumps is prescribed J
above 350*F and precluded below 300'F; and 7) a dedicated operator is required i
to terminate inadvertent HPSI or unnecessary charging pump operation if the LTOP system is not operable and the primary coolant temperature is between 385'F and 430*F.
The NRC staff finds that these restrictions are consistent with the licensee's commitments in the January 20 and 22, 1988 let;ers and acceptably protect against violation of the Appendix G limits whila maintaining acceptable protection against primary coolant system coolant loss.
The j
associated surveillance requirements for these restrict, ions are also acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
I j
An Environmental Assessment and Finding of No Significant Impact has been iss'Jed for this amendment (53 FR 4563?),
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4.0 CONCLUSION
We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and sc urity or to the health and safety of the puulic.
Date:
November 14, 1988 Principal Contributoi.
T. Wambach s
.