ML20008F521
| ML20008F521 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 04/09/1981 |
| From: | Finfrock I JERSEY CENTRAL POWER & LIGHT CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8104210132 | |
| Download: ML20008F521 (5) | |
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Jersey Central Power & Light Company Muson Avenue at PunchNwt Road 1
Mornstown fJew Jersey 07960 001 539 6111 rPRIL 9, 1981
>!r. Dennis S!. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Str. Crutchfield:
The attached is in response to your letter of December 8,1980 requesting additional info'mation relative tc, the containment isolation system at the Oyster Creek Nuclear Generating Station.
If you should have any questions concerning this information, please contact Str. J. Knubel (201-455-8753) of my staff.
Very truly yours, Ivan R. Finf ek, Vice President
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SEP Topic VI-4 i
1)
The Oyster Creek drywell atmosphere oxygen concentration must be less than 5.0% within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of placing the reactor rode switch in the "RUN" position.
The containment is inerted via the containment isolation vent and purge valves and the nitrogen supply system. Nitrogen is admitted to the torus by opening va lves V-28-17, V-28-18, V-23-15 and V-23-16 until the oxygen concentration is 4.0 to 4.5% (see Figure 1).
The drywell. atmosphere oxygen concentration is then reduced i n the same manner v ia va l ves V-27-1, V-27-2, V-23-13 and V-23-14.
Valves V-27-1 and V-27-2 are closd in order to increase drywell pressure to its cperating value, at this point valves V-23-13 and V-23-14 are closed.
Drywell and torus nitrogen makeup may be required during normal operation in order to maintain proper containment pressure and oxygen concentration.
If the DP between the torus and drywell increases to 1.4 psid, drywell valves V-23-21 and V-23-22 are opened until the DP is reduced to 1.2 psid.
High oxygen concentration in the drywell is reduced by opening valves V-23-152 until. the drywelI pressure is decreased to the 1.1 psig setpoint of the automatic make up-system. Valves V-23-1&2 are closed when the desired oxygen concentration is obtained.
High oxygen concentration in the torus is reduced by admitting nitrogen via valves V-23-19&20 until the oxygen content is below 3%..
Containment deinerting may commence 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to a sereduled shutdown.
The torus is purged by venting via valves V-28-17&I8 and opening V-26-16, V-26-18 and V-26-17.
The drywell is purged by venting via valves.-27-1&2 and opening V-27-3&4.
i Four containment i so l at ion va lves (V-23-21, V-23-22, V-28-18 and V-28-47) may be opened under isolation conditions if the reactor mede selector switch is i
placed in any mode other than "RUN" and a key lock bypess switch is operated.
The bypass switch overrides both the drywell high pr m ure signal and the 4
j reactor low-low water level signal. The vent and purge system is in accordance with Criteria 1, in that it provides e function other than containment isolation.
As a result of NUREG-0578, item 2.1.5a, a commitment was esce to mod i f y the vent and purge system such that it is single active failure proof for both operation and isolation.
In addition, the 8-inch, 12-inch, 18-inch, and 20-inch i
butterfly valves will be replaced with valves qualified to close ithin 5 seconds under accident conditions (BTP CSB-6-4).
The proposed modification, 1
which is scheduled to be installed by the end of the next refueling outage, is shown in Figure #2.
The valves will isolate via the same logic as the previous design, eithcr low-low reactor water level or high drywell pressure.- The new valves shall be ASVE 111, safety class 2 and IEEE Class IE.
Under normal operating conditions, the crywell and torus nitrogen makeup valves V-23-42, V-23-48, V-23-54 and V-23-60 may be opened and closed by manipulating their respective control switches. The valves will automatically.
Close upon receipt of an isolation signal.
Following an accident, the valves may be manually opened by placing the associated key lock switch into the bypass
- l position and by turning the respective control switch to the "CPEN" position.
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The operat ion of val ves V-23-41, V-23-47, V-23-53 and V-23-59 le the same as those above with these exceptions.
When the f ormer valves are open and the i
latter valves' control station is in the "AUT0" position:
a) Under normal operating conditions, the valves modulate to maintain the drywelI and torus pressure at the setpoint.
b) Under accident conditions, the valves modulate to maintain nitrogen flow at the setpoint.
i Under normal operating conditions, valves V-23-30 and V-23-36 can be opened or closed by manipulating their respective control switches.
The valves will 1
automatically open if the reactor mode switch is not in the "RUN" mode and the r
drywell pressure exceeds the setpoint.
In addition, the valves will automatically close if the exhaust duct pressure exceeds the setpoint or an isolation signal is received.
Under accident conditions, the valves may be i
manually opened by plac'ng the associated keylock switch into the bypass position and by turning the respective control switch to the open position. The operation of valves V-23-29 and V-23-35 is the same as those above except that with the former valves open and the latter valves' control station is in the "AUT0" position, the valves modulate to maintain vent flow at the setpoint value.
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- 2) The bypass function is provided by a key lock switch while the reset functions are provided by push buttons. The use of both the key lock switch and the reset buttons are procedurally controlled. No modification is intended.
- 3) Annunciation is provided, "VEF ISOLATION BYP SW 0FF NORMAL", in the main control room whenever the isolation valve bypass permissive switch is in other than the normal position.
- 4) The primary containment isolation initiation signals are the same as those which initiate core spray. Either low-low reactor water level (7 feet 2 inches above the top of the active fuel region; reactor water level switches RE-02-A i
thru D) or high drywell pressure (2 psig; drywell pressure switches RE-04-A thru D) starts core spray.
The subject containment vent and purge valves isolate in response to a high drywell pressure or low-low reactor water level condition.
The FSAR is in error.
JCP&L has committed, via NUREG 0737 Item 11.E.4.2, to utilize a containment high radiation signal to isolate tne vent and purge isolatin valves.
The i
moalfications will be implemented in accordance with the present schedule to provide e containment high radiation signal.
- 5) JCP&L sent a letter to the NRC dated October 28, 1980 concerning the SEP topic " Environmental Quali f ication of Safety-Reiated Equipment." The report attached to the subject letter addresses the stated concern.
- 6) The issue was addressed by NUREG 0578 Item 2.1.4 in a letter to the NRC dated April 10, 1980.
In addition, JCP&L anticipates that all two position control d
switches associated with the vent and purge isolation valves will be replaced with three position s.-itches Dy July 1, 1981. This will eliminate the need for-I the operator to reposition the switches pricr to resetting the containment isolation circuits.
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