ML20128K180
| ML20128K180 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/09/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20128K177 | List: |
| References | |
| NUDOCS 8507240058 | |
| Download: ML20128K180 (5) | |
Text
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NUCLEAR REGULATORY COMMISSION n
-l WASHINGTON, D. C. 20555 l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 89 TO FACILITY OPERATING LICENSE NO. DPR-28 VERMONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271 1.
INTRODUCTION Operating experiences, advances in the state-of-the-art, voids in some specific requirements, and nonuniform interpretations indicated the need for changes, clarifications, and improvements in the Standard Technical Specifications (STS) for inservice operability and surveillance require-ments for snubbers.
To reflect accumulated experience obtained in the past several years, the NRC staff issued Revision 1 of the snubber STS.
By. NRC Generic Letters dated November 20, 1980 to power reactor licensees (except SEP licensees) and March 23, 1981 to SEP licensees, the NRC requested all licensees to incorporate the requirements of this revision into their plant specific Technical Specifications (TS).
The revised STS included:
Addition of mechanical snubbers to the surveillance program; Deletion of the blanket exemption for testing of greater than 50,000 lb. rated capacity snubbers. (Snubbers of greater than 50,000 lb. capacity are now included in the testing program);
Deletion of the requirement that seal material receive NRC approval; Clarification of test requirements; Provision for in place testing; and Addition of a service life monitoring program.
Recently, by NRC Generic Letter dated May 3,1984, the NRC advised that licensees may choose to request a license amendment to delete the tabular listing of snubbers from their TS.
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DISCUSSION Vennont Yankee Nuclear Power Corporation (licensee) responded to the November 20, 1980 NRC request by letter dated April 7,1981 in which the licensee presented reasons why their snubber TS were appropriate and sufficient. The NRC Region I staff perfonned a plant site inspection dated May 26, 1983 and discussions were held with cognizant licensee's personnel concerning the bases of the snubber STS and differences in the licensee's snubber TS. By letter dated February 7,1984 the licensee submitted a request for license amendment and proposed snubber TS changes which addressed the majority of differences discussed during the site inspection.
Based on the staff's review of the licensee's submittal of February 7,1984, another site inspection, dated March 29, 1984, was performed by NRC Region I.
During this inspection a meeting was held with cognizant licensee's personnel and the licensee's TS.were compared term by term with the NRC model STS. At this meeting, the licbnsee's staff provided clarification which justified many of their proposed TS differences. The NRC staff determined that several of the differences would require further TS change or written justification to resolve the differences. These differences were the subject of the NRC May 3, 1984, Request for Additional Information (RAI) sent to the licensee.
The licensee responded to the RAI, by letter dated July 9, 1984, and provided information regarding each of the NRC requested items.
The licensee resolved the majority of the items by committing to revise the TS to agree with the STS or by providing an acceptable justification for the difference. Three of the response items required additional clarif-ication or a commitment from the licensee. A conference phone conversa-tion between NRC and licensee staffs was made on August 8, 1984 and agreements were reached on resolving these few remaining items.
The licensee's staff advised that the forthcoming snubber TS submittal would be revised to reflect the agreed-upon positions.
The licensee's July 9, 1984 response to the RAI, also indicated the licensee's intent to delete their snubber TS Tables based on the NRC Generic Letter dated May 3, 1984.
Therefore, licensee's letters dated May 17, 1983, May 20, 1983 and August 3,1983 which related to snubber TS Table additions and deletions due to system modifications have not been included within this discussion.
3.
EVALUATION By letters dated October 22, 1984 and November 6, 1984, the licensee resubmitted their revised proposed snubber TS changes, completely replacing the February 7,1984 submittal. The staff has evaluated this snubber TS resubmittal and has dctermined it to be in substantial agreement with the intent of the snubber STS and TS recently approved for Near Term Operating
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3 The Itcensee's proposed snubber TS has: 1) clarified and increased snubber operability and surveillance requirements, 2) defined testing and accep-tance criteria, 3) removed the exemption for testing snubbers of greater than 50,000 lb. capacity, and 4) included the method to functionally test snubbers of rated capacity greater than the capability of their testing machine.
The licensee's resubmittals included the TS agreed-upon positions of the NRC and licensee staffs phone conversation of August 8,1984 and the RAI response commitments and do not require additional comment. In performing this evaluation the staff recognized the licensee's proposed TS are in the custom (in lieu of STS) format and also that there would be certain items where a plant specific approach is warranted.
For example, the proposed TS does not contain mechanical snubber provisions, because only hydraulic snubbers are used with safety related systems at the facility.
Other variations between the STS and the licensee's TS and several items which are regarded noteworthy of explanation are addressed below.
3.1 Functional Testing of Large Snubbers The licensee's TS 4.6.I.1.c has been modified to remove the exemption for testing snubbers of greater than 50,000 lb. capacity. Removal of this exemption was one of the prime objectives of the STS.
The licensee's TS 4.6.I.1.c contains requirements for functional testing of snubbers of rated capacity greater than the capability of the testing machine based on the snubber vendor's correlative type procedure.
This involves testing of the large snubber components individually and in combination with a smaller snubber and calculating equivalent velocities and forces to enable appro-priate large snubber valve settings.
The licensee's TS 4.6.I.1.c requires:
- 1) testing and/or setting of the snubber valve assembly for proper lock-up and bleed velocity utilizing a cylinder that is within the testing machine capability,
- 2) checking for free stroke of the snubber cylinder, and 3) checking the pressure retaining capability of the snubber cylinder.
The staff has reviewed the licensee's large snubber functional test requirements, the snubber vendor's procedure to perform this testing, and recently approved TS which permit indirect testing.
The staff has also determined that the licensee has only one snubber that exceeds their test machine capability.
The staff has concluded that the licensee's large snubber functional testing meets the STS intent, and therefore is acceptable.
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4 3.2 Service Life Monitoring The licensee's TS does not contain the STS service monitoring pro-vision, however, the licensee's RAI response dated July 9, 1984 submitted information stating that their Plant Operating Procedures TS requires them to have detailed procedures in areas including surveillance testing, and preventive maintenance.
The licensee also described their restrictive maintenance practice of rebuilding and replacing seals on each snubber that is functionally tested and they noted that no functional test failures have been experienced since 1978. Additionally, the licensee's earlier response dated April 7, 1981, stated that their present snubber surveillance program required retention of maintenance records and that their maintenance program 1
requires periodic review of these records to determine failure trends to establish criteria to determine service life.
Based on the results oriented nil failure record, the staff's site verification that each snubber functionally tested is rebuilt, the relatively small number of snubbers (57 total),
the licensee's orderly maintenance records which contain service life information, the licensee's method of setting snubbers based on fluid viscosity at temperature, and the licensee's effective maintenance and surveil-lance program as evidenced by no functional test failures since 1978, the staff finds the licensee's position acceptable.
3.3 Functional Testing Frequency The licensee has modified their TS Bases to describe the functional testing during each " operating cycle" instead of refueling cycle.
The staff reviewed the licensee's TS and determined that the
" operating cycle" is defined in the TS whereas " refueling cycle" is undefined.
In addition, use of 'the term " operating cycle" is consistent with other TS equipment surveillance requirements.
Based on the above the staff finds the term acceptable.
3.4 TS Snubber Tables The licensee's proposed snubber TS does not contain a Table listing of snubbers.
The licensee's removal of the Table was based on the recent NRC Generic Letter dated May 3, 1984 which provided the choice.
The staff's plant site inspection dated March 29, 1984 verified that the licensee maintains a comprehensive listing of snubbers and records which document the results and dates of testing, inspections, repair, and installation of snubbers.
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5 Based on the verification of the licensee's records, the licensee's proposed TS which have now been modified to define which snubbers are required to be operable and the NRC Generic Letter of May 3,1984, the staff finds the licensee's proposed TS Table deletion to be acceptable.
Based on the review as described herein, the staff finds the licensee's proposed snubber TS submittal to be acceptable.
4.
ENVIRONMENTAL CONSIDERATIONS This amendment involves changes in the installation or use of a facility comoonent located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The staff has datermined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration ard there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
5.
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 this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Harold I. Gregg Dated: July 9,1985
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