ML19262A315
| ML19262A315 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/22/1974 |
| From: | John Miller METROPOLITAN EDISON CO. |
| To: | Knuth D US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19262A312 | List: |
| References | |
| NUDOCS 7910260642 | |
| Download: ML19262A315 (1) | |
Text
..
~\\
VM j -fy
~
@ld, ' dau. ',-an
/
,/
METROPOLITAN EDISON COMPANY.. : cmv oc anruvauevnunc cocrouncre /
POST OFFICE BOX 542 READING, PENNSYLVANI A 196o3 TELEPHONE 215 - 929 36o1 April 22, 197h Dr. D. F. Knuth, Director Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D. C.
20545
Subject:
Three Mile Island Nuclear Station Unit 1 Docket No. 50-289 Diesel Generators
Reference:
J. G. Miller Letter to D. F. Knuth dated 4/4/74
Dear Dr. Knuth:
You were notified on March 29, 1974, of a situation which may be considered reportable under 10CFR50.55(e), " Conditions of Construc-tion".
This situation related to the Diesel Cenerators.
The referenced letter informed you that the design agent was conducting a review of the diesel generator circuitry as a result of a recent problem involving starting of the units. This review has been completed.
As a result of this review the following design deficiency was uncovered.
The diesel generator has two (2) star: relays whose function is to operate contacts for two (2) air start solenoid valves.
The start relays energize to de-energize the air solenoid valves thua providing starting air to engine.
The circuit design was such that there were contacts from the low speed switch and lube oil switch in series with both start relays. The significance of this was that a fail-ure (speed or pressure switch not dropping out during engine shutdown) would disable both start relays. That is, a single failure (either switch) would deactivate both start circuits such that neither a manual or an automatic safeguards start could be accomplished. Both diesel generators were susceptible to this problem.
This deficiency has been corrected by installation of a field change approved by the design engineer.
Very trul: yours, 1485 h4
~ M 'd "
g4g a
J. G. Miller N 910 2 6 0 brh cc:J. P. O'Reilly
, Vice President