ML20002D891
| ML20002D891 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 10/09/1970 |
| From: | Haueter R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML20002D890 | List: |
| References | |
| NUDOCS 8101230318 | |
| Download: ML20002D891 (4) | |
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OccxtTca CONSUMERS POWER COMPANY UWC q
' OCT 141970r-h Docket 50-155 Regulatory Fire Cy.
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'l Addendum to Eighth, Winth and Twelfth Reports of 9
dE U DCCati CLigg Operation of Big Rock Pbint Nuclear Plant N
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\\<3 License No DPR-6 4
g TWELFTH SEMIANNUAL REPORT OF OPERATIONS The following information was inadvertently omitted y ry / / - I1' from Section I of the Twelfth Semiannual Report of Operations: ' ',
On December 12, 1969, high temperatures were experienced on Control Rod Drive D-5 while attempting to backflush a rod drive filter. The filter was properly valved to perform the backflushing operation; however, when the valve was opened to backflush the filter, it was opened too vide, reducing the cooling water header pressure thus allowing hot water to flow from the reactor vessel to the control rod drives.
Control Rod Drive D-5 temperature in-creased to 458 F.
Other control rod drives showed temperature in-creases, but did not exceed the 350 F temperature limit. The back-flushing operation was secured upon receiving indications of control rod drive system abnormalities and the system temperatures and pres-sures returned to normal. The backflushing procedure was replaced with a chemical cleaning procedure to prevent recurrence of this ty;e problem. The overheated drive was removed, dismantled and visually inspected during the February-March 1970 refueling cutage. No signs of damage.due to overheating were detected.
Prior to plant start-up on January 9, 1970, all containment isolation valves were test-operated as required.by the Technical 3
Specifications. The inside isolation valve (CV h031) on the dis-charge of the enclosure clean sump was found to be erratic in operation.
The coil on the associated solenoid valve (SV h869) was immediately replaced and the valve operated properly. Investigation revealed the replaced coil had a short in the windings and also revealed evidence of overheating. A high temperature coil was installed during the February-March 1970 refueling outage.
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7 Routine scram time testing prior to fuel loading during the
- February-March 1970 refueling outage revealed Control Rod Drive F-2 4
to have erratic scram times. The problem was traced to erratic venting of the.NC27-B solenoid valve th;L controls the scram inlet and outlet i
valves for Control Rod Drive F-2.
This valve was replaced and Control Rod Drive F-2 tested properly and consistently. An extensive investi-gation was conducted to determine the mode of failure. It was con-cluded that the most probable cause of failure was that the spring that returns the slug to the shut position upon de-energizing the solenoid had become disengaged from the slug. The manufacturer also agreed this was the most probable cause although neither the manufactur-er's nor the plant's testing programs could cause an identical failure.
This investigation was hampered because the plant repairman who per-formed the repairs discarded the slug because it showed. minor damage to the seat on the slug. Scram time test procedures have been revised to insure that improper venting of a scram solenoid valve will be de-tected. This was the first failure of this type at Big Rock Point.
4' While the plant was shut down on June 6,1970, the contain-ment isolation valves were tested. The dirty sump inside isolation.
valve (CV-h025) failed to' operate properly. The failure was traced to the solenoid pilot valve (SV-4891) and this valve was replaced prior to start-up. The dirty sump inside isolation valve then operated properly. The failed unit was bench-tested. The cause of the failure was. attributed to loss of resiliency of the seat material due to nor-mal wear.
EIGHTH AND NINTH SEMIANNUAL REPORTS OF OPERATIONS An error was made in the total radioactive materials of acti-4 vation and fission gases reported discharged in Section II-A of the Eighth and Ninth Semiannual Reports of Operation. These totals are corrected as follows:
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g,,,, r.,. yt yn i /d - Ji W Eighth Semiannual Report As Reported Corrected Value
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11/1/67-h/30/68 98 x 10 curies c.,s curies V
- N2hth Semiannual Report 3",48 ^ /0 b
5/1/68-10/31/68 h.61 x lo' curies 1 49 x 10 curies By Robett L. Haueter Electric Production Superintendent --
Nuclear Consumers Power Company Jackson, Michigan Date: october 9, 1970 Sworn and subscribed to before me this 9th day of October 1970.
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Notary Public, Jackson Cointy, Michigan My commission expires January 15, 1972 l
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