ML20010F774
| ML20010F774 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/27/1981 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Keimig R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20010F767 | List: |
| References | |
| NUDOCS 8109110311 | |
| Download: ML20010F774 (4) | |
Text
a PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 1881 -1981 PHILADELPHI A. PA.19101 SHIELDS L. DALTROFF ELacfarc Pm D CTION August 27, 1981 Docket Nos. 50-277 Re: Inspection No. 50-277/81-14 50-278/81-15 Mr.
R.
R.
Keimig, Chief Projects Branch #2 Division of Resident & Project Inspection US Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Keimig:
Your letter of July 29, 1981, forwarded combined Inspection Report Nos. 50-277/81-14 and 50-278/81-15 for Peach Bottom Atomic Power Station.
Appendix A addresces one item with respect to Unit 2 which does not appear to be in full compliance with Nuclear Regulatory Commission requirements.
This item of non-compliance has been categorized as a Severity Level IV and is restated below with our response.
Technical Specification 3.7.A.2 states in part:
" Primary Containment integrity shall be maintained at all times when the reactor water temperature is above 212 degrees F and fuel is in the reactor Vessel...."
8109110311 810903 PDR ADOCK 05000277 G
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Mr.
R.
R.
Keimig, Chief Page 2 1
Contrary to the above, on May 18, 1981, with fuel in the reactor vessel, primary coolant tcaperature in the reactor vessel was raised above 212 degrees F from 12:45 p.m. to 3:15 p.m. without primary contain.nent being in effect.
Response
As reported for Unit 2 by the Licensee in LER 2-81-31/3L, dated 6/17/81, the event occurred due to a lack of timely coordination between operations and maintenance personnel while shutdown cooling was out of service to repair the shutdown cooling suction outboard isolation valve (MO-2-10-17).
At about 7:00 a.m.,
shutdown cooling was secured for a repair which was estimated to take four hours.
Reactor coolant temperature, as monitored at the RWCU inlet, was about 110 degrees F.
Maintenance was not completed in the four hour time period and the system remained blocked.
At noon, the reactor coolant temperature had reached 170 degrees F at the RWCU suction inlet and steps were begun to restore shutdown cooling capability.
At 2:50 p.m., with RWCU suction temperature at 190 degrees F shutdown cooling was restored.
RWCU suction inlet temperature was 190 degrees F when shutdown cooling was restored,-however, this was not a representative reactor coolant temperature.
Neither reactor recirculatian pump was in service to provide forced recirculation and reactor level was lower than that required for natural circulation to occur.
Therefore, the RWCU inlet temperature was significantly lower than the reactor vessel water surface temperature.
This was due to thermal stratification as evidenced by reactor vescel steam space metal temperatures peaking at 231 degrees F and a reactor pressure of about six psig.
This inadequate mixing resulted in a portion of the reactor coolant exceeding 212 degrees F for approximately 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.
Overall coolant temperature was reduced below 212 degrees F in accordance with Tech. Spec. 3.7.A.3.
The original event was reviewed with operating personnel during beginning-of-shift meetings.
Operating personnel have been instructed to review and be aware of the decay heat removal consideration which are discussed in IE Circular 81-11.
Appropriate excerpts of IEC 81-11 have been distributed to all licensed personnel and shift Technical Advisors.
To prevent future occurrences of this nature existing procedures and administrative controls will be reviewed for adequacy in
1 e
Mr.
R.
R. Keimig, Chief Page 3 4
monitoring and maintenance of primary coolant temperature, l
providing redundant or diverse decay heat removal methods during l
all modes of operation, and specifying responses to lost or j
degraded decay heat removal capability.
Appropriate procedure and control changes will be made in accordance with IEC 81-11.
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If you have any further questions, please do not henitate to l
contact us.
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Very truly yours, t
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COMMONWEALTH OF PENNSYLVANIA :
ss.
COUNTY OF PHILADELPHIA S.
L.
Daltroff, being first duly sworn, deposes and says:
1 That he is Vice President of Philadelphia Electric Company, the Applicant herein; that he has read the foregoing response to Inspection Report Nos. 50-277/81-14 and 50-278/81-15 and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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Subscribed and sworn to b
before me thir28 day of C
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ELIZA7ETH H. BOYE NqtaMblic, Phila, Phita. Co.
My Commission 6pires Jan,30,1992
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