ML20087C345
| ML20087C345 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 08/03/1995 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20087C340 | List: |
| References | |
| NUDOCS 9508090157 | |
| Download: ML20087C345 (5) | |
Text
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UNITED STATES
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S NUCLEAR REGULATORY COMMISSION E
'f WASHINGTON. D.C. 3068H001 "s
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 83 TO FACILITY OPERATING LICENSE NO. NPF-42 WOLF CREEK NUCLEAR OPERATING CORPORATION WOLF CREEK GENERATING STATION DOCKET NO. 50-482 3.0 JNTRODUCTION By letter dated July 28, 1995, Wolf Creek Nuclear Operating Corporation (WCNOC) (the licensee) requested changes to the Facility Operating License No.
NPF-42 for the Wolf Creek Generating Station (WCGS). The proposed changes would delete the license condition stated in 2.C.(1), Attachment 1, that requires the pump in the keepwarm system of the emergency diesel generators (EDGs) to satisfy the requirements of the American Society of Mechanical Engineers (ASME) Code,Section III, Class 3 (ASME Code) requirements.
2.0 BACKGROUND
The purpose of the lube oil keepwarm pump is to circulate lube oil through the EDG while it is in the standby mode. This provides the following functions:
(1) maintain the oil in the sump in a warm condition to help ensure the EDG will start within the required 12 seconds, (2) prelubricate the essential engine components, and (3) maintain the oil purity.by continuous filtration (bypass flow) of the lube oil. The first condition is directly related to TS requirements, while the later two are measures to reduce unnecessary wear during surveillance tests and to help ensure long-term performance of the EDG.
On July 27, 1995, the keepwarm pump for A EDG failed.
Following that failure, the A EDG was declared inoperable and Technical Specification (TS) 3.8.1.1, Action b was entered.
This TS allows 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to complete the repairs and return the A EDG to cperable status or the unit would be required to be shut down. The declaration of inoperability maximized the safety of personnel working on the keepwarm pump.
On July 28, 1995, the mechanical overspeed trip device on the B EDG actuated due to a possible governor ad.iustment problem and the B EDG was declared inoperable and TS 3.8.1.1, Action f, was entered. This requires that at least one EDG be returned to operable status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or the unit would have to be shutdown.
A EDG was then started and ran until the lube oil temperature was returned to the required temperature band. The A EDG was then declared operable, with the failed keepwarm pump isolated. WCNOC remained in TS 3.8.1.1, Action b, because of the failure on the B EDG.
In order to maintain the A EDG operable, 9508090157 950803 ADOCK0500g2 DR
the A EDG is started periodically and the lube oil warmed.
This requires starting the engine every 3-6 hours.
The licensee has tried to obtain a repli. cement pump and repair part that satisfy the requirements of the ASME Ccde. However, the original manufacturer (Crane-Deming) is no longer is business and no other pump manufacturer is producing a pump the satisfies the ASME Code requirements. Replacement pumps are available that satisfy the performance requirements and are produced under a quality assurance program, but do not satisfy the ASME Code requirements.
Because of this unavailability of replacement parts or pumps and the necessity of periodic operation of the A EDG to satisfy operability requirements, on July 28,1995, the liensee requested the staff to exercise enforcement discretion to allow the installation of a non-ASME Code pump.
On July 28, 1995, the staff verbally approved the licensee's request and followed with a letter dated August 1, 1995.
3.0 [yALVATION The licensee has made a concerted effort to find replacement parts and complete pumps that satisfy the ASME Code requirements. The licensee has also stated that the operating history of the ASME Code pumps has shown them tr, be less reliable than the non-ASME pumps initially installed by the EDG vendor.
These non-ASME pumps were temporarily utilized at WCGS during startup of the unit. However, a license condition was added to the license that required the replacement of the non-ASME keepwarm pumps with pumps that satisfied the ASME Code requirements following the first refueling outage.
The licensee has proposed to delete the license condition that requires the replacement of keepwarm pumps with pumps that satisfy the ASME Code requirements.
In lieu of meeting the ASME Code, the replacement pumps would have the same performance characteristics, are seismically qualified, hydrostatically tested, and have been manufactured under an approved quality assurance program, essentially one step below an ASME Code pump.
Regulatory Guide (RG) 1.26, Revision 3, " Quality Group Classifications and Standards for Water, Steam, and Radioactive-Waste-Containing Components of Nuclear Power Plants," gives guidance on classification of components for application of ASME Code requirements.
Section B of RG 1.26 states that it does not cover systems such as instrument and service air, diesel engine and its generators and auxiliary support systems, diesel fuel, emergency and normal ventilation, fuel handling, and radioactive waste management systems, but that these systems should be designed, fabricated, erected, and tested to quality standards commensurate with the safety function to be performed.
Section C.2.b of RG 1.26 requires that cooling water and seal water systems or portions of those systems important to safety that are designed for functioning of components and systems important to safety, such as reactor coolant pumps, diesels, and control rooms, be Quality Group C (ASME Class 3).
The keepwarm pumps are not an integral component of the cooling water or seal water support systems for the EDGs. The licensee concluded that the keepwarm pumps can be considered Quality Group D components that are seismic Category 1 qualified.
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- Based on the above, the staff concludes that the deletion of the license condition requiring the installation, in the keepwarm system of the EDGs at WCGS, is acceptable. The pumps in the keepwarm system of the EDGs at WCGS shall be seismic, Category 1, qualified, designed, fabricated, erected and hydrostatically tested to an approved quality standard, commensurate to the safety function to be performed.
4.0 EMERGENCY CIRCUMSTANCES The licensee in its July 28, 1995, letter requested this amendment be processed as an exigent amendment. However, the staff is processing this as an emergency amendment. Following the failure of the A EDG keepwarm pump and the subsequent failure of the B EDG governor, the licensee restored the operability of the A EDG by running the diesel to warm up the lube oil to above the minimum temperature required to help ensure a 12-second start.
Since that time the A EDG has been operated periodically to maintain the lube oil temperature above the minimum temperature requirements.
If the A EDG was I
not restored to operable status.:nd maintained in an operable status, the unit would have to be shutdown within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
i Even before this pump failed, the licensee has been trying to obtain a replacement pump and repair parts that satisfy the requirements of the ASME Code. However, the original manufacturer (Crane-Deming) is no longer is business and no other pump manufacturer is producing a pump the satisfies the ASME Code requirements.
Replacement pumps are available that satisfy the performance requirements and are produced under a quality assurance program, but do not satisfy the ASME Code requirements. The staff is satisfied that the licensee has been diligent in pursuing an ASME Code pump.
Even with the B EDG restored to operable status, only 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> would be available before a plant shutdown would be required, unless the operability of the A EDG was maintained. While the periodic operation of the A EDG to maintain operability is acceptable for a short period, extended operation in that mode is not desirable.
Therefore, the staff has made a determination to process this application as an emergency amendment request pursuant to 10 CFR 50.91(a)(5).
5.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commission's regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant hazards considerations, if operation of the facility, in accordance with the amendment would not:
(1)
Involve a significant increase in the probability or consequences of any l
accident previously evaluated; or t
(2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3)
Involve a significant reduction in a margin of safety.
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This amendment has been' evaluated against the standards in 10 CFR 50.92.
It does not involve a significant hazards consideration because:
1 (1) This proposed deletion of the license condition does not involve a significant increase in the probability or consequences of an accident previously evaluated since the proposed installation of a non-ASME keepwarm pump does not change the function or performance requirements for the emergency diesel generator as described in the Updated Safety Analysis Report (USAR) and technical specifications. The design of the non-ASME pump will be to the same performance requirements as the ASME pump. The emergency diesel generator and associated keepwarm pump will continue to perform in a manner consistent with the assumptions in the USAR. There will be no degradation-in system performance, nor will there be an increase in the number of challenges to equipment assumed to function during an accident condition.
(2) This proposed deletion of the license condition does not create the possibility of a new or different kind of accident from any previously
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evaluated since the non-ASME pump will be designed to the same performance requirements as the ASME pump. The emergency diesel generator and associated keepwarm pump will continue to perform in a manner consistent with the assumptions in the USAR. No new accident scenarios, transient precursors, failure mechanisms, or limiting single failures are introduced. There will be no adverse effect or challenges
-imposed on any safety related system as a result of this emergency change to the operating license.
(3) This proposed deletion of the license condition does not involve a significant reduction in the margin of safety since the non-ASME pump was designed to the same performance requirements as the ASME pump and will perform in a manner consistent with the assumptions in the USAR. The emergency diesel generator and associated keepwarm pump will continue'to perform in a manner consistent with the assumptions in the USAR.
Accordingly, the Commission has determined that this amendment involves no significant hazards considerations.
6.0 1MTE CONSULTATION i
In accordance with the Commission's regulations, the Kansas State Official was notified of the proposed issuance of the amendment. The State official had no comments.
7.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, j
of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation 1
r-exposure.
The Commission made a final no significant hazards consideration finding with respect to this amendment. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22 environmental assessment need be prepar(b) no environmental impact statement or ed in connection with the issuance of the amendment.
8.0 CONCLUSION
The Commission has 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
J. Stone Date: August 3, 1995 i
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