ML20038A845
| ML20038A845 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 11/16/1981 |
| From: | Swartz E COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| REF-SSINS-6820 IEB-81-02, IEB-81-2, NUDOCS 8111240214 | |
| Download: ML20038A845 (6) | |
Text
m
/
s Commonwe::lth Edison
(
) one First National Plaza, Chicago, Imnois
(
) Address Reply to. Post Office Box 767
(
/ Chicago, lihnois 60690 Novembe r 16, 1981 Mr. James G. Keppler, Director I' f Directorate of Inspection and
-(
-i UOV,9 3 7gg * -f Enforcement - Region III U.S.
Nuclear Regulatory Commission 799 Roosevelt Road
<,.,,,,,l"*' "7' "o
Glen Ellyn, IL 60137
Subject:
Byron Station Units 1 and 2 Braidwood Station Unit s 1 and 2 1)
Response to I.E.
Bulletin 81-02 Supplement 1,
" Failure o f Gate Type Valves to Close Against Differential Pressure" 2)
Supplemental Response to 50.55(e)
Deficiency Report 81-03 NRC Docket Nos. 50-454/455/456/457 Reference (a):
T.
R.
Tramm letter to J.
G.
Keppler dated July 24, 1981.
(D):
J.
G.
Keppler letter to Cordell Reed dated August 18, 1981.
(c):
E.
D. Swartz letter to J.
G.
Keppler dated September 15, 1981.
Dear Mr. Keppler:
Reference (b) requested Commonwealth Edison Company to review Bulletin No. 81-02, Supplement 1, for applicability to our plants under construction and report the results within ninety (90) days.
The enclosure to this letter is provided to fulfill this ninety (90) day requirement for our Byron and Braidwood Stations.
Reference (c) fulfilled this ninety (90) day requirement for our LaSalle County Station.
The enclosure to this letter is also intended to supplement our Reference (a) response to the 10 CFR 50.55(e) reportable defi-ciency (number 81-03).
However, the enclosure includes some changes to the information submitted in Reference (a).
Specifically, the
" Consequence o f Failure" uescription has been modified in accordance with the Westinghouse determination, and six (6) valves have been added to the list (SI6808A,B,C,0, 8809A,B).
Additionally, the maxi-mum differential pressure and specific corrective action determina-tions for Byron Station have been made and are reported herein.
The bl l 8111240214 811116 PDR ADOCK 05000454 yG,I c, 0 19m G
J.
G.
Keppler Novembe r 16, 1981 specific modifications for the Braidwood units are expected to be available by March, 1982.
Finally, modifications are expected to be completed on Byron Unit 1 by January 1, 1982.
The schedule for completion of the Byron Unit 2 and Braidwood Units 1 and 2 modifications will be determined and submitted by April 1, 1982.
Our estimate of the hours expended in the review and prepa-ration of the enclosed supplementary Byron and Braidwood report is five and one half hours.
This does not, however, account for the Westinghouse efforts in preparing their determination on this matter.
Additionally, the manhour estimates for corrective action have not been determined.
To the best of my knowledge and belief, the statements contained herein are true ani correct.
In some respects these statements are not based upon my personal knowledge, but upon information furnished by other Commonwealth Edison employees.
Such information has been reviewed in accordance with Company practice and I believe it to be reliable.
Please address any questions you may have concerning this matter to this office.
Very t ruly yours, fb f
$x-E.
Douglas Swartz Nuclear Licensing Adminstrator Enclosure cc:
Director, NRC O f fice o f Inspection and Enforcement Region III Inspector - Byron Region III Inspector - Braidwood SUESCRIBED AND SWORN to of 8
/Mf.4I4.k.8.
Notary Public 1m 2878N
e 4
j ENCLOSURE i
J COMMONWEALTH EDISON COMPANY BYRON STATION UNITS 1 and 2 BRAIDWOOD STATION UNITS 1 and 2 RESPONSE TO I.E. BULLETIN 81-02 SUPPLEMENT 1 i
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Valve W EMD Consequence Byron Station Valve Location Rodel Maximum of Failure to Required
,' Function Number Reference P (psi) (1)
Close Modification"
=
- 'VCT Outlet LCV-1128,C 4GM72FB 100 Failure of either of two valves A
n i
in series to close reduces redundancy of providing
?
isolation.
Alternate valve i
will provide isolation.
RWST to LCV-ll2D,E 8GM72FB 200 Failure of either of two valves B
Suction CCP in parallel from the RWST to the suction of the CCP's reduces redundancy of providing isolation 2
of RWST during the recirculation phase following a LOCA.
Isolation will be provided by a check valve in series with the two paths.
RHR Suction 8701B 12GM88SEH 700 Failure of either of the two B
I' solation inner isolation valves'in
~
(Inner) series to close reduces the redundancy of providing isolation.
Isolation is provided by closing the outer valve.
RHR Suction 8701A 12GM88SEH 700 Same as 8701B/8702B except for B
Isolation 8702A closing the inner valves.
(Outer)
(1)
As flow approaches zero, final functional requirement.
A:
Adjust open and close torque switchsetting.
8:.
Change to limit control closure, change gear ratio.
Valve W EMD Consequence Byron Station Valve Location Model Maximum of Failure to Recuired Function Number Reference P (psi) (1)
Close Modification RHR 8716A, B 8GM 74FE 300 Failure of either of the two.
A Discharge valves in series to close reduces redundancy of providing low head train separation during cold leg recirculation phase following a LOCA.
Train separation can be achieved by closing other valve.
RHR Heat 8804A 8GM84FE 300 Failure of valve to close A
Exchanger precludes realignment of RHR for Discharge to normal operation.
(Valve is CCP Suction opened f or recirculation phase following a LOCA).
RHR Heat 8804B 8GM74FE 300 Same as '8804A A
Exchanger Discharge to SI Pump Suction RWST to SI
.8806 8GM72FB 200 If valve fails to close, B
Pump Suction backflow into RWST would be prevented by a check valve.
(Valve is closed for recirculation phase following a LOCA).
(1)
As flow approaches zero, final functional requirement.
A:
Adjust open and close torque switchsetting.
B:
Change to limit control closure, change gear ratio.
I Y
e
~.
-3_
_...j Valve W EMD Consequence Byron 'Statipn Valve Location Model Maximum of Failure to Required i
Function Number Reference P (psi) (1)
Close Modification a
CCP Suction 8807A,B 6GM72FB 200 There are two valves in parallel Unit 1-A SI Pump 8924 (8807A,B) in series with one Unit 2-B Suction (8924).
Failure of any of these valves to close will not preclude Crossover isolation.
SI Pump 8923A,B 6GM72FB 200 If either valve fails to close, Unit 1-A Suction the other valve will provide the Unit 2-B Cross Connect separation.
(Valves are closed to provide SI pump train separation).
Accumulator 8808A,B,C,D 10GM88FN 0
Valve is closed to prevent RCS None Discharge pressurization during cold shut-down operation.
If valve fails to close, the accumulator may be depressurized by venting the N2 to containment.
i RHR Cold 8809A,B 8GM78FN 200 Valve is closed for switchover None Leg Injection from cold leg to hot leg recirculation.
Failure of valve to close will degrade flow to hot legs.
i.,
(1)
As flow approaches zero, final functional requirement.
A:
Adjust open and close torque switchsetting.
B:
Change to limit control closure, change gear ratio.
4 090lb