ML20138G429
| ML20138G429 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 12/06/1985 |
| From: | Ainger K COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20137Y697 | List: |
| References | |
| NUDOCS 8512160323 | |
| Download: ML20138G429 (4) | |
Text
/
De 2
[ ~~ N Commonwealth Edison
} or.e First National Plaza. Chicago. Ithnois T's
(
Address Reply to: Post Office Box 767 N
Chicago, Illinois 60690 December 6, 1985 -
L Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation i
U.S. Nuclear Regulatory Commission l
Washington, D.C.
20555 i
Subject:
Byron Station Unit 1 Essential Service Water System f
NRC Docket No. 50-454
Dear Mr. Denton:
As a result of the review of the Byron LCO Relaxation Program, concerns have arisen regarding the calculated contribution of the Unit 1 essential service water (ESW) system to the estimated core melt frequency during the period i
before operation of Byron Unit 2.
These concerns were discussed with the NRC staff at meetings on December 3 and December 6, 1985.
As proposed during the meeting on December 6, 1985, Commonwealth Edison will enhance the reliability of the unit 1 ESW system by making a Unit 2 ESW pump available during operation of Byron Unit 1.
The unit 2 ESW pumps are in their final stages of
^
preoperational testing and can be connected to the Unit 1 ESW system through cross-tie piping existing in the the design.
The following is a description of the administrative controls that will be put into effect to govern the availability of a unit 2 ESW pump until Byron Unit 2 is in operation.
I Prior to entering Mode 4, a Unit 2 ESW pump will be AVAILABLE to support Byron Unit 1 operation.
The Unit 2 ESW pump will be considered AVAILABLE if it is capable of being manually started'and crosstied to the Unit 1 ESW system.
The i L. y,_.A... t - availability of. a. Unit: 2 ESW pump will be ensured by incorporating x 2.
the following surveillances into the Station Surveillance Program.
1.
At least once per day, Bus 241 will be verified to be energized if the 2A ESW pump is the AVAILABLE pump or i
BUS 242 will be verified to be energized if the 2B ESW pump is the available pump.
2.
At least once per day, the following valves will-be verified open or capable of being operated from the main control board.
)
8512160323 851210 PDR ADOCK 05000454
', D. - v.
1 ".,.y v.9-...
1;.
- t PDR r
.-- f 4
s y
p i
l w
w
2-If 2A ESW pump - valves 2SXO33, 2SXO34, 2SX005,,*
is AVAILABLE 2SX001A, 2SX016A, 2SX027A If 2B ESW pump - valves 2SX005, 2SX001B, 2SXOi6B, is AVAILABLE 2SX027B 3.
At least once per 31 days, the AVAILABLE pump will be t
operated for 15 minutes.
g If neither Unit 2 ESW pump is AVAILABLE, either the 2A or 2B ESW pump will be restored to AVAILABLE status in 7 days or Byron Unit 1 will be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 in the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
If only one Unit 1 ESW pump is OPERABLE and neither Unit 2 ESW pump is AVAILABLE, immediate action will be initiated to i
restore either a Unit 2 ESW pump to AVAILABLE status or a Unit 1 ESW pump to OPERABLE status.
Byron Unit 1 is presently shutdown.
Prior to entering Mode 4, operating procedures will be revised to instruct control room operators to crosstie the Unit 2 ESW system to the Unit 1 ESW system in the event both Unit 1 ESW pumps become inoperable.
Initial training on these procedures will be provided to control room operators involved with the startup of Unit 1.
i The actions described above will eliminate concerns regarding the calculated contribution of the Unit 1 ESW system to the estimated core melt frequency during the period before operation of Byron Unit 2.
These actions will no longer be necessary when Byron Unit 2 begins to operate.
Please address any questions you may have regarding this matter to this office.
Very truly yours, 47.
I K. A. Ainger Nuclear Licensing Administrator cc:
Byron Resident Inspector
~
0 4
), 4, NYi [ O"
-hf{.
,,_.p-N *.
.1
, -"g i
,x 2
~
-e
~
'.i.N lo N'
^'
i r
a e.
r
.._.y-
,,rm
,e
,____,-..w_ _ _,,. _
,.__..y.
r~-
JN
<d A
3 I
This issue is still being investigated for any potential application to other W plants.
Sincerely, Hugh L. Thompson, Jr., Director Division of PWR Licensing-A
Enclosure:
1.
Memo from Thompson to Denton dated 12/5/85 2.
Letter from Ceco to Denton dated 12/6/85 cc:
J. Keppler F. Miraglia
.T. Speis R. Bernero W. Russell Distribution Docket or Central File i
NRC PDR*
Local PDR*
PD#5 Reading File H. Thompson J. Stevens M. Rushbrook D. Eisenhut i
i 0FC :PD#5
- PD#5
- D: DIR NAME :JStevens
- VSNoonan
- HThompson DATC :
/ /85
/ /85
/ /85 0FFICIAL RECORD COPY f
i t
- -... =
/
ESWS to the estimated CMF during the period before operation of Byron Unit 2.
This issue is still being investigated for any potential application to other i
W plants.
/
Sincerely, i
?
j
/
l Hugh L. Thor.pson, Jr., Director Division of PWR Licensing-A
Enclosure:
1.
Memo from Thompson to Denton dated 12/5/85 2.
Letter from CECO to Denton dated /12/6/85 1
cc:
J. Keppler F. Miraglia T. Speis R. Bernero e
W. Russell Distribution
/
4 i
i Docket or Central File
/
NRC PDR*
/
Local PDR*
/
i PDf5 Reading File
/
1 H. Thompson J. Stevens
/
M. Rushbrook D. Eisenhut i
/
!0FC ~
j j
,#5
- PDt5
- DIR l___
- NAM
- JStevens
- VSNoona
- HThompson
' DATE :lz /( 0/85_ _ _ _ _ : _ _ _ _ _ _ _ _ _ _ _ _ : y 7_)/8 5
- / V//d
- / /85 0FFICIAL RECORD COPY l
/
/
/
/
s I
i
-..,.. -, - - -. - - - -