ML19317G116
| ML19317G116 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/03/1977 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| Shared Package | |
| ML19317F827 | List: |
| References | |
| NUDOCS 8002210804 | |
| Download: ML19317G116 (2) | |
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%s SNUC SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 S Street, Box 15830 Sacramento, califernia 95813; (916) 452 3211 October 3, 1977 gj.' '
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Director of Regulatory Operations
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ATTN:
Mr. R. H. Engelken 4
p-U NRC Operations Office, Region V 3 ~~~
1990 N. California Boulevard K
Walnut Creek Plaza, Suite 202 L. U " " '
Walnut Creek, California 94596
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7, Re: Operating License DPR-54 jk
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Docket No. 50-312
'-g Followup Report: RO 77-10
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Dear Mr. Engelken,
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The Sacramento Municipal Utility District hereby submits a followup
,V repor*. to Reportable Occurrence 77-10 concerning functional testing of safety system hydraulic snubbers. As stated in the original report sub-mittal of September 29, 1977, following the failure of the first two snubbers tested to meet the lockup / bleed velocity acceptance criteria j
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during the refueling interval surveillance, an expanded program was i
g initiated to test all eighty-one (81) snubbers subject to functional test-ing. Of those snubbers tested, thirty-five (35) required some type of maintenance prior to installation.
Eleven of the units failed to lock up within the capabilities of the testing equipment. Of the five Bergen-Patterson units in this category,
.f three exhibited signs of control valve seat damage. No apparent problem could be found with the other two snubbers. All failed to lock up in the extension direction and one failed in the retraction direction as well.
The five units were repaired as necessary, were cleaned, had the seals and oil replaced and were retested. Five of the ITT Grinnell snubbers exper-iencing lockup failure did so because of improper adjustment, the sixth had an improperly assembled valve block. The units were assembled and adjusted properly, some were cleaned and had seals and oil replacet as a precautionary measure and all were retested.
Inability to meet conservative lockup / bleed velocity criteria led
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to maintenance on 24 additional snubbers. For seven Bergen-Patterson snubbers Z
no defects were apparent. Two units showed control valve seat damage which was repaired. All nine units were rebuilt and retested. All but one of the fif teen Grinnell units which did not satisfy the criteria mere!7 re-quired re-adjustment for proper operation. No problem could be found with the last snubber, so it was cleaned and the seals and oil were replaced.
Following the corrective measures stated above all thirty-five snubbers successfully passed the functional test and were reinstalled in
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3 Director of Regulatory Operations October 3, 1977 Mr. R. H. Engelken The Bergen-Patterson snubbers involved in this occurrence were Models HSSA-3-6, HSSA-10-6 and HSSA-20-6.
The Grinnell snubbers were Models 200 and 201. As these units cover a wide range of sizes, this factor did not appear to be significant.
Functional testing of safety system hydraulic snubbers will continue in accordance with the surveillance requirements as stated in Technical Ei Specifications Section 4.14.4.
Respectfully submitted,
.f J. J. Mattimoe Assistant General Manager and Chief Engineer g[
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