05000334/LER-1977-105-03, /03L-1 on 771011:during 18-month Surveillance testing,13 Hydraulic Snubbers Appeared to Have Suspect Lockup & Bleed Rate Valves.All Snubbers Have Been Rebuilt & Tested to New Generic Values
| ML19263C329 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/13/1979 |
| From: | Werling J DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML19263C328 | List: |
| References | |
| LER-77-105-03L, LER-77-105-3L, NUDOCS 7902210261 | |
| Download: ML19263C329 (2) | |
| Event date: | |
|---|---|
| Report date: | |
| 3341977105R03 - NRC Website | |
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Update Report U.S. NUCLEAR REGULATORY COMMISSION NRC FORM 3G6 (7 771 -
Previous Report Date 11/10/77 LICENSEE EVENT REPORT CONTROL BLOCK: l l
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60 61 DOCKET NUMB ER tid 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBASLE CON 3EQUENCES h l During performance of 18-month surveillance testing of 13 hydraulic snubbers, the l
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Based l 10 l 3 l l snubbers appeared to have lock-up and biced rate values which were suspect.
I upon subsequently established acceptance criteria, all snubbers in Table 3.7-4 of l
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l Tech Spec 3.7.8.12 have been rebuilt and tested to the criteria.
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s Lo 16 I I TTT Grinnell snubbers requirea for safe operation of the pinne hnve been chanced I
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Attachment to Updated LER 77-105/03L Echver Valley Power Station Duquesne Light Ccmpany Docket No. 50-334 A review has determined that the worst case post-lockup thermal transient which could be experienced by a QA Category I pipe and associated snubber would be the inadvertent auxiliary spray through the pressurizer auxiliary spray line.
This transient would occur when the auxiliary spray line injected 100"F water into the 4 inch pressurizer normal spray line that was initially at 547"F.
The resultant maximum thermal growth rate at the location of the Category I snubber was calculated to be 1.36 inches per minute.
Since the actual bleed rate setting on test was set to be greater than or equal to 2 inches per minate, the thermal growth of the piping during lock-up can be accomodated.