ML19340A912
| ML19340A912 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/07/1973 |
| From: | Brian Lee COMMONWEALTH EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML19340A910 | List: |
| References | |
| NUDOCS 8009080586 | |
| Download: ML19340A912 (3) | |
Text
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n.o ONE PlRST NATIONAL PLAZA
- CHICAGO. ILLINOIS Address Deply to.
POST office BOX 767
- C H IC A G O, ILLINOIS 60490 February 7, 1973 Mr. Boyce H. Grier Regional Director Directorate of Regulatory Operations - Region III U.S. Atomic Energy Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Response to Noncompliance Items for DPR-2 Identified During the November 28 through December 1, 1972 Inspection, AEC Dkt 50-10
Dear Mr. Grier:
This letter is in response to your letter of January 18, 1973, which was concerned with tuo items of non-compliance found on Dresden Unit 1 during a recent inspection.
Item No, l.was concerned with Paragraph B.15.b(1) of the Technical Specifications which specifies 100 F as a maximum 0
limit for the emergency condenser shell-side water temperature.
On' November 30, 1972, the shell-side water was observed to be 110 F and although gradually decreasing, remained above 100 F through December 5, 1972.
By December 6, the temperature 0
0 had decreased to 100 F and. has remained at a level of 100 F or less through January 29.
.The significance of operating the reactor with the 0
emergency condenser shell-side water temperature above 100 F should be considered in light of a document entitled " Interim Core Cooling Analysis (ICCA) ".
The ICCA is a comprehensive study of the transients which would be experienced by Dresden Unit 1 reactor during a loss of coolant accident.
This study concludes that the heat removal capacity of the emergency condenser is adequate to maintain the fuel cladding tempera-FEB 1 e 1973 -
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{ himonwealth Edison Company {;.,
_,j Mr. B. H. Grier 2 -'
February 7, 1973 ture_ below required levels -even if the emergency condenser shell-side water temperature is as high as 212 F at the time of ECCS initiation.
In view of the analysis presented in the ICCA, the station feels _that the period of time the 0
emergency condenser water temperature was above 100 F was not a period which either presented a significant safety hazard or compromised a safety system as described in any Safety Analysis Report.
It should be realized that the emergency condenser shell-side water temperature is a very strong function of the air temperature observed-in the-upper regions of the spherical containment.
Because of this local air temperature dependence i
and lack of cooling equipment in the area, there is little that can be accomplished operationally to place the emergency condenser water temperature significantly lower than the local area air temperature.
Since local air temperature as high as 130 F can be observed on occasion, obvious (i.fficulty is encountered in keeping the water temperature below 100 F.
Immediately following the deviation of the emergency condenser water temperature from Technical Specification limits in November, the Nuclear Licensing Administrator was contacted and a water temperature linit was discussed, but after verbal discussion with the Directorate of Licensing, the subject was dropped.
The Nuclear Licensing Administrator is presently' involved in preparing a Technical Specification change which would request that the maximum water temperature limit be increased to a value more compatible with the local air temperature in the area.
Until such a time as this change is approved and incorporated in the Technical Specifications, shell-side temperatures in excess of 1000F, should they occur, i
will be reported in accordance with Paragraph J.5 of the Technical Specifications as presently written.
Item No. 2 was concerned with the failure of the diesel-generator to Bus 15, circuit breaker.
On August-25, 1972, as a precautionary measure during a tornado warning, the diesel-generator was operating in a standby condition, i.e.,
at rated RPM and voltage but not synchronized to a bus..
Following the termination of
monwealth Edison Companyg
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~ Fir. B. H.'Grier February 7, 1973 the tornado warning, an attempt was made to synchronize the diesel-generator to Bus 15 to provide the diesel with some power operation. _The first attempt to synchronize failed.
Immediately following the failure of the breaker to close, it was " racked out" and then " racked in" again.
A second' attempt to synchronize was successful.
At.the earliest opportunity following the breaker failure, a complete inspection of the breaker was made.
The inspection revealed no evident cause for the failure.
All subsequent tests of breaker operation were successful.
Although it cannot be determined with'a high degree of certainty, it is believed that the mechanical mechanism in 4
the breaker which senses whether the breaker is " racked in" may have been the cause of the failure.
i Because of its importance in a loss of offsite power situation and because it has on other occasions exhibited 2
l certain anomalies, the breaker will be replaced during the next refueling outage.
The failure which occurred on August 25 will be reported in the Dresden Station July through December Semi-Annual Report.
Any future failures of this type, should
.they occur, will be reported as abnormal occurrences in accordance with Paragraph J.5 of the Technical Specifications.
Should you require any additional information, please let us know.
Very truly yours, 4
GM Ubd O9
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Byr n Lee, Jr.
Assistant to thk(
President 5
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