ML20040G119
| ML20040G119 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/03/1982 |
| From: | Murray T TOLEDO EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| K82-200, RO-NP-09-82-01, RO-NP-9-82-1, NUDOCS 8202110285 | |
| Download: ML20040G119 (3) | |
Text
.
A-TOLEDO
~
%mm EDISON February 3, 1982 LogNo.K(2-200 File:,RR 2 (NP-09-82-01)
Docket No. 50-346 (5
1*a License No. NPF-3 8
s.
%CrqED Mr. James G. Keppler 1'Ois b S Regional Administrator, Region III 9
Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission y[
799 Roosevelt Road 4
f Glen Ellyn, Illinois 60137 p
Dear Mr. Keppler:
Enclosed are two copies of Reportable Occurrence UP-09-82-01, which are being submitted to you in accordance with Technical Specification 6.9 to provide 30 day written notification of this occurrence.
Yours truly, l y D 'Y M
+
Terry D. Murray W.
Station Superintendent Davis-Basse Nuclear Power Station TDM/ljk Enclocure cc:
Mr. Norman Haller, Director Office of Management and Program Analysis Encl:
2 crpies Ohio Environmental Protection Agency Northwest District Office Encl; 1 copy Mr. Luis Reyes NRC Resident Inspector Encl:
1 copy THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO, OHIO 43652 F202110285 820203 PDR ADOCK 05000346 FEB
~5 1982 ZC2,19 J
_PDR
a TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE REPORTABLE OCCURRENCE NP-09-82-01 DATE OF EVENT: January 4, 1982 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Environmental Technical Specification 2.1.1, maximum discharge temperature above ambient lake temperature limit was exceeded during an unusual weather change Conditions Prior to Occurrence: The unit was in Mode 1 with Power (MWT) = 2757 and Load (Gross MWE) = 914.
s Description of Occurrence: On January 4, 1982 at 0555 hours0.00642 days <br />0.154 hours <br />9.176587e-4 weeks <br />2.111775e-4 months <br />, the control room re-ceived the lake delta temperature high alarm T191. This indicates that the differ-ence between the inlet lake temperature and the station discharge temperature to the lake had risen to 19'F.
Environmental Technical Specification 2.1.1 limits this temperature limit to 20*F.
The operators took action to attempt to reduce the temp-erature of the station discharge. They verified the dilution pump was on and diverted more of the makeup water for the circulation water system to increase dilution flow.
Ilowever, this was not enough to prevent the limit from being exceeded at 0805 hours0.00932 days <br />0.224 hours <br />0.00133 weeks <br />3.063025e-4 months <br /> on January 4, 1982. Additional response was taken by reducing cooling tower blow-down.
This lowered the station discharge temperature and brought the difference to within limits such that at 0957 hours0.0111 days <br />0.266 hours <br />0.00158 weeks <br />3.641385e-4 months <br /> the alarm point T191 had returned to normal.
Designation of Apparent Causa of Occurrence: The cause of the temperature increase was an unusual weather change.
Between 0100 and 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on January 4, 1982, the air temperature was reading about 34*F.
Ilowever, the wind direction shifted and was now out of the south, gusting to 30 mph with an increasing air temperature such that at 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br />, the air temperature was 50*F.
This caused the cooling tower basin temperature to increase to above 79"F and this raised the discharge temperature by more than 3*F.
Since the lake temperature is very stable, the result is an increase in the difference between inlet and discharge temperature. The response of the opera-tors was proper but the response was not initiated soon enough to prevent exceeding the limit. There are two alarms to aid the operators. T189 (lake delta temperature rising) alarms at 15'F but since operation is routinely in that differential tempera-ture range, procedures do not require action at that alarm. The second alarm T191, at 19"F requires actions to be taken, but by then it is usually too late. T189 needs to be modified to provide adequate warning.
Analysis of Occurrence:
There was no danger to the health and safety of the public or to.utation personnel. The 20*F delta temperature limit was exceeded by less than 1*F and was out of limit for less than one hour. This slight increase should not have had any adverse environmental impact.
,e
F a
TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE REPORTABLE OCCURRENCE NP-09-82-01 PAGE 2 Corrective Action: To effect a response that will prevent the 20' delta temperature from being exceeded, alarm point T189 (lake delta temperature rising) will have its setpoint changed from 15'F to 17'F.
This change will require imaediate operator action to reduce d1scharge temperature rather than waiting until T191 (19'F) alarms. A memo will be written to all reactor operators to require that when the T189 alarm is received, that action be taken to reduce blowdown and divert make makeup as needed to keep the 20*F from being exceeded. It also will require that at 17*F, the delta temperature be. trended to allow a closer monitoring of the temp-erature changes. Facility Change Request 80-124"has requested the deletion of this-Environmental Technical Specification requirement as a result of the Yellow Creek Decision.
I Failure Data: - Previous occurrences were reported in NP-09-81-02, NP-09-81-01, NP-09-80-01, and NP-09-78-03.
h 4.
l s
4 s
4 T
4 m
I e
f
)
M
,f
?
.