ML20093D029
| ML20093D029 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 10/09/1984 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| ULNRC-942, NUDOCS 8410110044 | |
| Download: ML20093D029 (4) | |
Text
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i UNION ELECTRIC COM PANY 1901 GRATIOT STREET ST. Louts, MISSOURI October 9, 1984 "T'"*ff,,"f,"*
oo~uo r. Sc~~nt vece psertion*st ST. LOUIS. MISSQU RI SS I S S Mr. Harold R.
Denton, Director Office of Nuclear Reactor Regulation U.
S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Denton:
ULNRC-94 2 DOCKET NUMBER 50-483 UNION ELECTRIC COMPANY CALLAWAY PLANT, UNIT 1 ACCUMULATOR VENT VALVE REWORK
Reference:
SLNRC 84-079 dated 5-10-84 Recent discussions with the Resident Inspector, Project Manager, and NRR technical reviewers have indicated the need for a submittal providing justification for the temporary capping of the accumulator vent lines and deferral of rework as discussed hereinafter.
The reference letter discussed the rework of 20 Target Rock solenoid valves to correct design deficiencies reported pursuant to 10CFR50.55(e).
This rework, consisting of the replacement of existing field cabling with high temperature wiring and Conax connectors, was to have been performed prior to initial criticality for the subject valves (EP-HV-8950A,B,C,D,E,F).
However, prior to entering mode 3 (hot. standby) it was discovered that these vent valves were leaking to the extent that the required accunulator. pressures were not being maintained.
Due to the excessive nature of this leakage, a temporary modification to cap these vent lines was implemented after performing an engineering review and obtaining concurrence from Westinghouse.
Currently, the vent lines for accumulators A and C (containing EP-HV-8950A,D,E) have been capped.
This leakage problem will be corrected by installing new, machined valve plugs which are being presently. manufactured.
Leakage from the other three vent valves has been reduced to acceptable levels, thus these vent lines were not capped.
Rework per the reference letter for all six vent valves has been deferred.
As stated in the safety grade cold shutdown FMEA submitted in FSAR Table 5.4A-3, failure of these vent valves has a negligible effect on plant safety as long as the Class lE
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8410110044 841009 hCP PDR ADOCK 05000493 g
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'Mr. Harold R.-D nton October 9, 1984 Page.2 discharge isolation valves are-available (EP-HV-8808A, B,
C, D).
If any of these isolation valves were unavailable, the affected accumulators could be vented via the group D nitrogen supply line and air operated valve EP-HCV-943'shown on FSAR Fig.
6.3-1, sheet 4.
Although the air supply for this valve is non-Q, it is expected to be available for the scenario requiring this venting.
l The air compressors serving this valve are shed from the Class IE buses on an SIS but may be~ manually realigned to these buses
-(FSAR Section 9.3.1.2.2).
All rework, including installation of the new valve plugs and_ rewiring per the reference letter, will be performed at the first outage of sufficient duration after acquisition of the necessary hardware.
Very truly yours, Donald F.
Schnell GGY/siz
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STATE OF MISSOURI )
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Donald F. Schnell, of lawful age, being first duly sworn upon oath says that he is Vice President-Nuclear and an officer of Union Electric Company; that he has read the-foregoing document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and
- that the facts therein stated are true and correct to the best of his
- knowledge, information and belief.
By Donald F. Schnell Vice President Nuclear SUBSCRIBED and sworn to before me this ay o 198 n,.,u p,,m./
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cc:
Gerald Charnoff, Esq.
Shaw,.Pittman, Potts & Trowbridge 1800 M. Street, N.W.
Washington, D.C.
20036 Nicholas A. Petrick Executive Director j
SNUPPS i
5 Choke Cherry Road.
Rockville, Maryland 20850 John H. Neisler Callaway Resident Office U.S. Nuclear Regulatory Commission RR91 Steedman, Missouri 65077 William Forney Division of Projects and Resident Programs, Chief, Section lA U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Little Callaway Resident Office U.S. Nuclear Regulatory Commission RR91 Steedman, Missouri 65077 l
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