ML18051B004
| ML18051B004 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 07/13/1984 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Dewitt R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| CAL, NUDOCS 8407200152 | |
| Download: ML18051B004 (2) | |
Text
Docket No. 50-255 Consumers Power Company ATTN:
Mr. R. B. DeWitt Vice President Nuclear Operations 212 West Michigan Avenue Jackson, MI 49201 Gentlemen:
CONFIRMATORY ACTION LETTER I'UUL 1 3 1984 IE FILE copy This refers to a reportable event which occurred on July 3, 1984.
Cable tray section identified as CP250 installed at elevation 590' inside the containment contained several safety-related cables including cables to.the pressurizer heaters which were observed to have been degraded (damaged insulation) by excessively high temperatures.
The excessive heat was apparently confined to the area where a one hour rated fire barrier (OHRFB) was installed in 1979 to meet the 10 CFR 50 Appendix R requirements.
Based on discussions between W. Shafer.of our office and D. VandeWalle of your staff, we understand that you will take the following actions prior to commencing power operations:
- 1.
Install a temperature monitoring device in the cable tray within the fire barrier. This detector will provide the capability to continually monitor the fire barrier temperature from outside containment.
The temperature shall be monitored once per shift. If the monitored tempera-ture reading exceeds 70°C, the surveillance frequency shall be increased to twice per shift. If the monitored temperature reading exceeds 80°C, the plant shall be placed in hot shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
If the temperature monitoring device fails or becomes inoperable, it shall be made operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
We understand that this program will continue on a once per shift basis until the fire barrier temperature has been stable for seven consecutive days following attainment of 95% of full power.
The frequency may be reduced to once per day for the next 30 days, provided the temperature remains stable. Following 30 days of stable temperatures, the frequency may be reduced to once per week for the next three months.
At the end of the three month period, the monitoring program may be discontinued, provided the temperature remains stable. If, at any time, the temperature increases more than 5°C, between any two consecutive readings, the surveillance frequency will be increased to twice per shift.
184012001-528-46713 I
~DR ADOCK 05000255 S
Consumers Power Company 2
- 2.
Measure the phase imbalance in all pressurizer heater power cables.
Each pressurizer heater power cable having a phase imbalance which exceeds 6 amperes will be de-energized.
If further evaluation indicates that increased imbalance is acceptable, the allowable imbalance may be increased, and the circuits re-energized. Additionally, evaluation of the possibility that the phase imbalance condition was the source of the heat which caused the thermal degradation of the cables will be completed within 30 days of issuance of this Confirmatory Action Letter. If the evaluation of the phase imbalance shows no significant impact on cable heating, the pressurizer power cables may be returned to service.
- 3.
Inspect the other cable trays inside containment wrapped with the one hour fire barrier and notify this office if additional damage is identified.
Please let us know immediately if your understanding differs from that set forth above.
cc:
D. J. VandeWalle, Nuclear Licensing Administrator R. W. Montross, Manager DMB/Document Control Desk (RIDS)
Resident Inspector, RIII Ronald Callen, Michigan Public Service Commission RIII f
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- L. Spessard11 James G. Keppler Regional Administrator RIU
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