ML19337B428
| ML19337B428 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/09/1980 |
| From: | Murray T TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| RO-NP-09-80-01, RO-NP-9-80-1, NUDOCS 8010020372 | |
| Download: ML19337B428 (3) | |
Text
.
TOLEDO
%mus EDISON September 9, 1980 L80-1069 FILE: RR 2 (NP-09-80-01)
Docket No. 50-346 License No. NPF-3 Mr. James G. Keppler Regional Director, Region III Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
Etc.losed are two copies of Reportable Occurrence NP-09-80-01, which has been revised.
The revisions to the report are indicated by a "1" in the left margin of each page.
Please destroy your previous copies of this report and replace with the attached revision.
Yours truly,
/mO Terry D. Murray Station Superintendent Davis-Besse Nuclear Power Station TDM/ljk Enclosure cc:
Mr. Norman Haller, Director Office of Management Program Analysir Encl:
2 Ohio Environmental Protection Agency Northwest District Office Encl:
1 OdY ss i f SEP 2 2 G80 THE TCLEDO ED: SON COMPANY ECISCN PLAZA 300 MACISCN AVENUE TOLECC CHf0 43652 80100so 372.
3
~
o TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE REPORTABLE OCCURRENCE NP-09-80-01 1
DATE OF EVENT: January 16, 1980 and February 10, 1980 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Discharge temperature for station liquid effluents exceeded 200F limit above lake te=perature The unit was in Mode 1, with Power (MRT) = 166 and
. Conditions Prior to Occurrence:
Load (Gross MWE) = 0.
Description of Occurrence: On January 6,1980 during normal plant startup, the 200F temperature differential limit between station liquid effluent discharge and lake temyerature was exceeded.
Environmental Technical Specification (EIS) 2.1.1 specifies that the maximum discharge lake water temperature for station liquid effluents shall not exceed 20 F above ambient tempera ture. When the limit is exceeded, dilution water is to be' supplied by the dilu-tion pump to keep the discharge temperature dif ferential within the 1 Lait.
The 20 F temperature differential limit was observed to have been exceeded at the following times: G700 hours and 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on January 6, 1980; 0000 houra, 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />, and 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on January 7,1980; and 0600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> on January 8,1980.
On January 16, 1980 at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />, the unit was operating at 100% power and the 20 F temperature dif f erential limit was exceeded again.
During each of the occurrences the temperature differential limit was exceeded by approximately 1 F to 5 F.
On February 10, 1980, again during normal plant startup, the 20 F temperature differ-1 ential limit between station liquid ef fluent discharge and lake temperature was ex-ceeded.
The dilution pump was operating during each of the occurrences but failed to maintain the liquid effluent temperature within the 20 F limit.
Designation of Apparent Cause of Occurrence: The apparent cause of the occurrence was 1l procedural deficiency. On January 6, 7, 8, and February 10, 1980, the plant was operat-ing with the cooling tower in bypass mode causing the cooling tower basin temperature to be elevated above normal operating temperature during startup, thus producing a high station liquid effluent temperature. The combination of high station liquid effluent temperature and low lake temperature caused the temperature differential limit to be i
exceeded. The dilution pump was operating per SP 1104.09, Circulating Water System and Cooling Tower Operation, but was unable to provide the adequate cooling effect and pre-vent exceeding the 20 F temperature diff erential limit.
9 N
O a
TOLEDO EDISON C0K?ANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE PAGE 2 REPORTABLE OCCURRENCE NP-09-80-01 On January 16, 1980, the unit was operating at 100% power with all circulating water High station liquid effluent temperature was caused by the combina-pumps operating.
tion of unseasonably warm weather and reduced cooling tower efficiency due to both control fiume isolation valves being inoperable. The combination of high station liquid effluent temperatere acd low lake temperature caused the temperature dif fer-ential limit to be exceeded. Again, the dilution pump was operating per SP 1104.09 but was unable to prevent exceeling the 20 F temperature different tal limit.
Circulating Water System and Cooling Tower Operation Procedure, was defi-SP 1104.09, cient of adequate guidelines to maintain station liquid effluent temperature within the 20 F limit beyond just verifying the dilution pump being on.
There was no danger to the health and safety of the public Analysis of Occurrence:
or to station personnel.
It is believed that the slight iacrease in temperature above the discharge limit did not cause environmental damage.
Corrective Action: On January 6, 7, and 8, 1980, the station liquid effluent tempera-ture returned to within the 20 F limit when the circulating water flow was transferred from the normal startup bypass mode of operation and directed through the cooling tower.
16, 1980, the service water discharge was diverted from the forebay to the On January collection box which reduced station liquid effluent temperature to within the 200F ILnit.
On February 10, 1980, the station liquid effluent temperature returned to within the 1
20 F limit by reducing the cooling tower blowdown.
SP 1104.09, Circulating Water System and Cooling Tower Operation Procedure, has been modified to provide additional guidelines to the operators to assist in maintaining 3
station liquid ef fluent temperature within limits.
Failore Data: A prior occurrence of the temperature limit being exceeded was reported in Licensee Event Report NP-09-78-03, i
I i
4 e
e.aweg
_.. -..