ML20214W656
| ML20214W656 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 12/04/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20214W652 | List: |
| References | |
| NUDOCS 8612100359 | |
| Download: ML20214W656 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION o
l WASHINGTON, D. C. 20505 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 97 TO FACILITY OPERATING LICENSE NO. DPR-28 VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271
1.0 INTRODUCTION
Recently, the staff (Ref. 1) identified a potential generic problem with wear rings for Bingham-Willamette Model 16 x 18 x 26 CVIC pumps. These pumps are used in the RHR system at Vennont Yankee. By letter dated July 11,1986 (Ref. 2), Vermont Yankee outlined its enhanced monitoring program for the four RHR pumps, including a plan to inspect / repair these pumps during the 1986-1987 operating cycle. Vermont Yankee had planned to perform this work during the 1987 refueling outage; however, in response to staff concerns, this schedule was accelerated to connence during the 1986-1987 operating cycle. Due to the scope of the work associated with the on-line inspection / repair, it is anticipated that a pump could be inoperable for more than the seven days currently allowed by Technical Specifications. Therefore, an extension of the current Limiting Condition of Operation and a modified Surveillance Requirement has been requested by the~ licensee. By letter from W. Murphy, Vermont Yankee Nuclear Power Corporation, to H. Denton, Nuclear Regulatory Commission (Ref. 3),
Technical Specification (TS) changes were proposed for Vermont Yankee Nuclear Power Station to permit an RHR pump to be inoperable for up to 14 days instead of the 7 days currently allowed by Technical Specifications.
The licensee also proposed changes in testing of the RHR pumps during the inspection period. According to the present technical specifications, if one RHR pump is inoperable, the remaining RHR pumps are to be tested daily to demonstrate their operability. The licensee is proposing to test the remaining operable pumps only on a monthly basis.
2.0 EVALUATION The Emergency Core Cooling System (ECCS) for Vermont Yankee Nuclear Power Station (VYNPS) consists of the following systems:
a High Pressure Coolant Injection System b
Automatic Depressurization System c
CoreSpraySystem[Twoloops,eachloopconsistsofone100%
capacity pump, each pump getting emergency power from a different diesel]
(d) Low Pressure Coolant Injection (LPCI) Mode of RHR.
[Twoloops, each loop consists of two 33 1/3% capacity pumps, each pump ]in the loop getting the emergency power from a different diesel 8612100359 861204 PDR ADOCK 05000271 P
s The 1icensee is proposing to take the RHR pumps out for inspection one at
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a time, each for a period of up to 14 days. The staff required additional assurance of a reliable power supply to the ECCS during the RHR pump' inspection / repair period.
The. licensee in Reference 4 stated the availability of an additional off-site power source. The Vernon Hydro-Plant is used for providing an alternate source of off-site power.
According to the licensee, power transfer from the hydro-plant to the
. station power can be done in a matter of seconds from the VYNPS control room. Also, the licensee has committed to advise the plant operators of the need for the switching action to ensure power supply for the ECCS.
The staff judges that these features provide additional assurance of the availability of power for the ECCS components.
The elimination of alternate testing which the licensee has. proposed is consistent with the staff current practice for ECCS Surveillance Testing as indicated in BWR Standard Technical Specifications.
If the existing test requirement is left intact, this would result in daily challenges to the system for up to 14 days. The testing outage time and the repeated tests will reduce the overall reliability of the systems. This would, in effect, reduce the margin of safety for these systems.
For these reasons, the staff agrees that no alternate testing should be required. The remaining active components will be tested monthly, and demonstrated operable in accordance with Technical Specifications. This is acceptable.
The proposed Technical Specification change is an addition to Sections 3.5.A.3 and 4.5.A.3.
This change is requested only during the RHR pump impeller wear ring inspection / repair to be conducted'during the 1986-1987 operating cycle. Only one RHR pump is to be taken out for inspection at any time. The licensee has an additional off-site power source immediately available and accessible from the control room and has comitted to alerting the operators to the importance and use of the power supply. On this basis we find the proposed changes acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S This amendment chages a requirement with respect to installation or use
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of a facility component located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the j
types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation i
exposure. The Commission has previously issued a proposad finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR J
i 51.22(c)(9).
Pursantto10CDR51.22(b),noenvironmentalimpact statement or environmental assessment need be prepared in connection with i
the issuance of the amendment.
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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 security or to the health and safety of the public.
5.0 REFERENCES
(1) NRC IE Information Notice No. 86-39 Dated May 20, 1986, " Failures of RHR Pump Motors and Pump Internals."
(2) Letter, VYNPC to USNRC, FVY 86-62 Dated July 11, 1986 "RHR Pump Impeller Wear Rings."
(3) Letter, VYNPC to USNRC, FVY 86-78 dated August 28, 1986 " Changes to Technical Specifications for the 1986/1987 Operating Cycle Inspection / Repair of the RHR Pump Impeller Wear Rings."
(4) Letter VYNPC to USNRC, FVY-86-102 dated November 3,1986.
" Response to Request for Information - Vermont Yankee Proposed Change No. 135."
Principal Contributor:
G. Thomas Dated: December 4, 1986 i
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