ML20090D388
| ML20090D388 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 07/03/1973 |
| From: | Schneider R NIAGARA MOHAWK POWER CORP. |
| To: | Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 5329, NUDOCS 8302280060 | |
| Download: ML20090D388 (2) | |
Text
-
r O
O
~
NIAGARA MoH AWK PoWCR CORPORATION NIAGARA MOHAWK ~
[
300 ERIE DOULEVARD WEST SYRACUSE, N Y.13202
.e July.3, 1973, p
h r
~,
,l N
h
, o k
p
@n /kED :
D
,g b/J j'
~
A Mr. Donald J. Skovholt Assistant Director for Reactor Operations fo%j Nr Division of Reactor Licensing Q 4 rO,y g
b6S United States Atomic Energy Conraissfon Y
Washington, D. C.
20545 g
g ca
Dear Mr. Skovholt:
/
Re: Provisional. Operating License:
DPR-17 Docket No.:
50-220 This is to report a condition relating to the operation of Nine Mile Point Nucicar' Station, Unit #1, in which, during routinc surveillance testing of the turbine anticipatory trip bypass switches, (Barksdale D2T-A12SS) two out of the four were found to exceed the value specified in the instrument surveillance check list. Technical Specifications 2.1.2. (i) states:
"The generator load rejection scram shall be
^
initiated by the signal for turbine control valve fast closure due to a loss of oil pressure to the acceleration relay any time the turbine first stage steam pressure is above a value corresponding to 833 Mwt, i.e.
45 percent of 1850 Mwt."
Technical Specifichtion'2.1.2.(j) states:
"The turbine stop valve closure scram setting shall l
be initiated at 5 10 percent of valve closure (stem
/
position) from full open whenever the turbine first stage steam pressure is above a value corresponding l
l to 833 Mwt, i.e. 45 percent of 1850 Mwt."
On June 29, 1973, at appro,:imately 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br /> during routine surveillance testing, tuo out of the four (one,in RPS channel 11 and one in RPS channel 12) Turbine anticip3cory trip bypass switches were found to actuate at a value of 365 psig and 366 psig (approximately 824-826 Mwt) l or approximately 5 and 6 psi above the instrument surveillance checklist i
value of 360 psig. The remaining tuo switches were found within specifications.
Notification of this deviation from the accepted value
.I for calibration was made on June 30,.1973, to Mr. Brickly of Region I, Division of Regul" -
Operation.
5329 e
O p
g t'
COPY SENT REGION b
S
/
(3
- 2 Mr. Donald Jw..kovholt
<.ty 3, 1973 a
,,, [
'U.S. Atomic Energy Commission
-.f -
The switches were instrument calibrated on May 25, 1973 and found correct' at that. time. The two switches actuating at 365 and 366 psig were recalibrated to read 357 and 358 psig.
To prevent possible recurrence of this incident and to insure that
't a turbine trip-will provide a near instantaneous reactor scram above 455 power ths Barksdale 02-13 A 6 B were calibrated lower than 360 psig (357 and 358 psig) and thus lower than 45' power. These will be rechecked in two weeks to insure that the instrumentation is not drifting.
In view of the fact that: (1) Redundancy was provided in the circuitry.which would have caused a reactor scram at the 360 psig first stage steam pressure setting following a turbine trip, (2)
The instrument surveillance checklist value for first stage steam pressure relates to a value less than that called for in Technical Specifications (806-810 Mwt), and (3) That even with the higher pressure the limit of7833 Mwt trip actuation was not exceeded; it is concluded
_qbat there age no implications or effects on the safety or health of the general public.
Very truly yours,
.c jr
-f Original signed by - R.R. Schneider t.
~
- /'
Rudolph R. Schneider'
~jj '
Vice President - Electric Operations
, f i i RRS: cm '
/.
o p "
1
.