ML19270G399
| ML19270G399 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 05/29/1979 |
| From: | Short T OMAHA PUBLIC POWER DISTRICT |
| To: | Stello V Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7906060278 | |
| Download: ML19270G399 (5) | |
Text
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- +J Omaha Public Power District 1623 HARNEY s
OMAHA. NEBRASKA 68102 e TELEPHONE 530-4000 ARE A CODE 402 May 29, 1979 Mr. Victor Stello, Jr., Director Division of Operating Reactors U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Reference:
Decket No. 50-285
Dear Mr. Stello:
In accordance with URC Inspection and Enforcement Bulletin 79-01, dated February 8,1979, the Omaha Public Power District gave 24-hour notice, by letter dated May 15, 1979, that certain safety-related electrical equiptent installed at the Fort Calhoun Station had failed to meet environmental qualification criteria. This letter provides, by attachment, a detailed written report addressing this subject.
The report clearly demonstrates that the health and safety of the public is not jeopardized by this situation.
Sincerely, f'
f.3 fj. E. Short T
Assistant General Manager TES/KJ'4/3JH:j=m
- Attach, cc:
Mr. Robert W. Reid, Chief Operating Reactors Branch Ho. k
". S. Nuclear Regulatory Commission Washington, D. C.
20555 Mr. K. V. Seyfrit, Director U. S. Nuclear Regulatory Ccmnission Office of Inspection and Enforcemen; Region IV 611 Pcytn Plaza Drive, Suite 1000 Arlington, Texas 76011 2274 346 LeBoeuf, Lamb, leiby & Ma:Rae 1333 New Ra=pshire Avenue, tuite 1100 Washington, D. C.
20036 790costq77
/fdol 25 W
Attachment All Automatic Switch Conpany (ASCO) solenoid valves were identified in the Fort Calhoun Station as being unqualified for service in a IDCA environment. Of these, the 19 valves listed belov have solenoid valves with plastic internals which could potentially be damaged in a LOCA en-vironment such that valve repositioning could occur.
Solenoid Normal Energize Accident Fail-Safe Solenoid
_ Valve No.
Drawing State to:
Position Position Model PCV-742A GHDR ND Open Closed Closed LB-8316315 11405-E-53 PCV-Th2C GEDR ND Open Closed Closed LB-8316315 11405-E-53 HCV-250hA CHDR ND Open Closed Closed 832CA26 11405-E-59 HCV-2506A GHDR ND Open Clcsed Closed 8320A26 11h05-E-59 HCV-2507A GEDR ND Open Closed Closed 8320A26 11405-E-59 PCV-2909 GEDR ND Open Closed
' Closed 8320A7 11h05-E 42 PCV-2929 GEDR ND Open Closed Closed 8320A7 11h05-E h2 PCV-2949 GHDR ND Open Closed Closed 8320A7 11h05-E h2 PCV-2969 GHDR ND Open Closed Closed 8320A7 11h05-E-42 HCV-724A GHDR ND Close Closed Cpen 8320Ah2 llh05-E-53 HCV-72kB CHDR ND Open Open Closed 8320A42 11h05-E-53 HCV-725A GHDR ND Close Closed Open 8320Ak2 11kOS-E-53 HCV-7253 GHDR ND Open Open Closed 832CAk2 11h05-E-53 HCV-1107A GHDR NE Close Open Open 832CA8 11405-E kh HCV-1108A GHDR NE Close Open Open 8320A8 11405-E-44 Page 1 of k 2274 347
Attachment (Continued)
Solenoid Normal Energise Accident Fail-Safe
- Solenoid Valve F,.
Drawing State to:
Position Position Model j
HCV-881 GHDR NE Close Closed Open 8320A102 ll405-E-49 HCV-882 GHDR NE Close Closed Open 8320A102 llh05-E-49 HCV-883A GHDR NE Close Closed Open 8320A86V ll405-E-49 HCV-88hA GHDR NE Close Closed Open 8320V86V llh05-E 49 Specifically, it is the manufacturer's opinica that at some time after the initiation of a LOCA, the radiation and high temperature may degrade the plastic internals of these solenoid valves, possibly resulting in re-positioning of safety-related valves without a signal for repositioning, provided an air source is available for the valves. However, this does not affect the valves' ability to initially assume safe positioning.
It should be noted that the re=aining unqualified ASCO solenoid valves, not listed above, in the manufacturer's cpinion, vill go to and remain in the accident position throughout a LOCA and therefore undergo no repositioning.
In order to assure that the health and safety of the 7ablic is not jeopardised, and that continued operation is justified, the District has taken the folleving measures:
(1)
New qualified solenoid valves vill be ordered, and replacement of these valves will begin upon receipt and be ec=pleted during the 1960 refueling outage. A test progran vill be initiated, if necessary, to determine qua2ifi:ation o. these new valves.
(2)
The plant operators have been instructed to fail instrument air to containment during post-LOCA ccnditions which potentially cause solenoid failures.
Failure of instrument air vill en-sure that these safety-related valves are maintained in their safe position.
It is emphasised that failure of instrument air to containment will net jeopardise the ability to safely shut down the plant and =aintain it in a safe shutdcwn condi-tion.
(3)
The manufacturer of the solenoid valve is of the opinion that all valves vill shift to their accident position during the initial stages of the LOCA.
It is not until scme time after the initial stages of a LOCA that the combination of radiatica and high te=perature may degrade the plastic intarnals of these solenoid valves, possibly resulting in repositioning of the safety-related valves without a signal for repositioning, pro-vided instrument air is available.
To guard against this Pag 2 of k 2274 ;48
s Attachment (Continued) undesired condition, the program of Step 2 (above) has been incorporated into plant procedures.
(4)
For all those valves in the initial list which function as containment isolation valves, redundant valves have been sup-plied outside the containment for added protection against the consequences of a LOCA. For convenience, these redundant valves are listed below:
Valve No.
Redundant (Outside Containment) Valve HCV-881 VA-280 (locked closed)
HCV-882 VA-289 (locked closed)
HCV-883A HCV-8833 HCV-88hA HCV-88hB HCV-1107A HCV-11073 HCV-1108A HCV-11083 PCV-Th2A PCV-Th23 these valves are presently
' failed closed as part of con-PCV-Th2C PCV-7h2D. tainment purge limitations HCV-25ChA HCV-250h3 HCV-2506A HCV-25C6B r
HCV-2507A HCV-25073 PCV-2909/2929/29h9/2969 HCV-2983 and locked closed valve SI-185 The following gives a brief description of the functions of the 19 valves previously listed:
PCV-Th2A/C
- Containment Purge Supply and Exhaust Valves: these valves are triggered by a CIAS signal to their ac-
- cident, i.e.,
fail-safe position.
HCV-250hA
- Reactor Ccolant Sample Isolatica Valve:
this valve's control circuitry is triggered by a CIAS signal.
HCV-2056A/
- Steam Generator Slowdown Samples Lines: these valves 2507A are triggered to their accident / fail-safe positien by a CIAS signal to the valves' control circuitry.
PCV-2909/2929/ - Safety Injection Leakage Pressure Ccatrol valves :
2949/2969 these valves go to their accident / fail-safe position upon receipt of an SIAS signal.
Page 3 of h 227L 349
Attachment (Continued)
HCV-724A/B
- Containment Charcoal Filter Dampers:
these valves 725A/B go to their accident positicn upon receipt of a VIAS signal. This allows the valves to align for the
" charcoal filtering mode" during/after the accident.
HCV-1107A/
- Steam Generator uxiliary Feedvater Isolation Valves:
1108A these valves attain their opened accident position upon receipt of a CIAS signal.
HCV-881/882
- Containment Hydrogen Purge Fan Isolation Valves:
these valves go to their accident position upon re-ceipt of a CIAS signal to the control circuitry of these valves. These valves attain their fail-safe position upon solenoid de-energization or loss of air to the feeding solenoid valves.
HCV-383A/88hA - Hydrogen Analyzer Isolation Valves:
these valves go to their accident position upon receipt of a CIAS signal. These valves attain their fail-safe positior.
upon solenoid de-energization or loss of air to the feeding solenoid valves.
2274 350 Page 4 of L