ML20084D626
| ML20084D626 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/29/1971 |
| From: | Hoyt H COMMONWEALTH EDISON CO. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 10584, NUDOCS 8304120140 | |
| Download: ML20084D626 (2) | |
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2 Commonwealth Edison Company ONE FIRST NATIONAL PLAZA
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Dresden Nuclear Power Station R. R.
11 Morris, Illinois 60450 s
Janua ry 29, 1971 Dr. Peter A. Morris, Director Division of Reactor Licensing U.S. Atomic Energy Commission,
Washington, D.C.
20545
SUBJECT:
LICENSE DPR-19. DRESDEN NUCLEAR POWER STATION UNIT #2, SECTION 6.6.C.1 OF THE TECHNICAL SPECIFICATIONS
Dear Dr. Morris:
This is to report a condition relating to the operation of the station wherein, durjng_quarterlgaurv_qillrice testing of the High Pressure Coolant Injection System (HPCI) on 12/31L70, the indicated HPCI pump flow
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was less than the value specified in Section 4.5.C.1 of the Technical Specifications and there was a failure to declare the system inoperable.
On January l 9,_1971 at 9: 23 p.m., quarterly _surveillanceps_dl ting was conducted on the HPC1 system.
Results of the test indicated the,HP pump flow to be less than the 5000 gpm specified in section 4.5.C.1 of the Technical Specifications. Accordingly the HPCI system was declared inoperable and surveillance on those systems required to be operabic by Section 3.5.C.2 was begun. Additionally, Instrument Mechanics were called in to determine the cause of the low flow indication.
Testing on all systems required to be operable by Section 3.5.C.2 was complete by 6:10 a.m. on January 20, 1971.
Calibration checks performed by the Instrument Mechanics deter-mined that due to a calibration shift in a square root converter in the flow indication circuitry, the indicated flow was 450 gpm less than the actual HPCI pump flow.
Following recalibration of the square root converter, HPCI flow surveillance was conducted on January 20, 1971, at 11:30 a.m. and flow in excess.of 5000 gpm was demonstrated.
The HPCI system was then declared to be\\ operable.
[g f By applying the 450 gpm calibration correction to the results of the January 19th surveillance test, pad can conclude that the HPCI
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systemunsalsopumpinginexcessof5000/gpmonthatdateand-that in fact therequirementsofsection4.5.C.1hacIbbenmet.
8304120140 710129 COPY. SENT REGION 4
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Dr. Peter A. Morris Page 2 January 29, 1971 During a subsequent audit of another HPCI surveillance test conducted December 31, 1970, it was discovered that the flow recorded on the surveillance data sheet for this test was less than that required by Section 4.5.C.l.
The HPCI system, however, was not declared inoperable following the December 31st test.
It is our belief that the square root converter calibration error mentioned earlier was also influencing the flow indication during the December 31st test and that actual HPCI system flow on that date was in excess of Section 4.5.C.1.
In view of the failure to decla re HPCI inoperable, immediately following the indicated low flow on December 31, 1970, the following corrective measures are being instituted:
1.
HPCI Surveillance data sheets will be revised to include the actual Technical Specification Limits, where applicable, adjacent to the data collected during the test, for comparison purposes.
2.
An effort will be made to schedule instrument calibration checks prior to certain surveillance tests, to maximize the confidence in data collected during the surveillance tests.
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H. K. Hoyt Superintendent HKH:dmc 4
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