ML19340E989
| ML19340E989 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 01/09/1981 |
| From: | Bayne J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 JPN-81-7, NUDOCS 8101160459 | |
| Download: ML19340E989 (5) | |
Text
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POWE9 AUTHORITY OF THE STATE OF NEW YORK to CoLUMaus CIRCLE NEW YORK. N. Y. too19 GEORotT.stamY 42127 397.6200 opsnatswa orrecss JOHN W. SOSTON JOHN S. DYSoN
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January 9, 1981 a,,c,7,r,ri aac=
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Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Mr. Thomas A. Ippolito, Chief Operating Reactors Branch No. 2
'~
Division of Licensing FitzPatrick Nuclear Power Plant
Subject:
James A.
Docket No. 50-333 Electrical Override Criteria NUREG-0737, Item II.E.4.2
References:
1.
NRC letter, T.A.
Ippolito to G.T. Berry dated July 18, 1980 2.
PASNY letter, J.
P. Bayne to T.A.
Ippolito (JPN-80-58) dated December 16, 1980 3.
PASNY letter, P.J. Early to T.A.
Ippolito l
(JPN-80-50) dated August 15, 1979 f
Dear Sir:
Submitted herein (Attachment 1) are responses to the NRC questions in Enclosure 1 of Reference 1.
The response to question 1 provides a description of the proposed modifications for the FitzPatrick plant in accordance with NUREG-0737 Item II.E.4 Position 6.
As previously indicated in Reference 2, this modification will not be implemented by January 1, 1981.
It is expected, however, that this modification will be com-pleted during the next refueling outage tentatively scheduled for October 1981.
NUREG-0737 Position 6, also requires that the purge valves be sealed closed until such time as the required modification to prevent simultaneous override of all safety signals, is com-pleted.
The use of the purge and vent system, although limited, is necessary during normal plant operation, as previously des-cribed in Enclosure 1 to Reference 3.
Thus, in lieu of main-l taining the valves closed and sealed at all times, administrative bOl s
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. procedures have been implemented at the FitzPatrick plant such that prior approval from the NRC s taff wil.' be requested prior to overriding the safety actuation signals.
Responses to the NRC questions in Enclosure 2 to Reference 1 are currently under preparation and will be submitted in the near future.
We trust that the information provided herein satisfies your concerns.
Should you have any questions regarding this matter, please do not hesitate to contact us.
Very truly yours,
- _ O.
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J. -P. ' B ayi q w -
e Senior Vice President Nuclear Generation
ATTACHMENT 1 REQUEST FOR ADDITIONAL INFORMATION JAMES A.
FITZPATRICK NUCLEAR POWER STATION CONTAINMENT PURGING DURING NORMAL PLANT OPERATIONS ELECTRICAL OVERRIDE CRITERIA QUESTION 1.
The NRC position that the override of one type of safety actuation signal must not cause the blocking of any other type of safety actuation signal to isolation valvesa is not met.
Your response to question 5b states "in the current design, bypasses of multiple safety c tuation signals can be initiated by a single override action."
Describe how you will modify these' circuits.to eliminate this design deficiency.
Provide your schedule for com-pletion of this modification.
RESPONSE
The system actuation signal for containment vent and purge system is composed of the following individual safety actuation signals:
(i)
Drywell Pressure High (>2.7 psig)
(ii)
Reactor Water Level Low (<12.5 in.)
(iii)
Reactor Building common ventilation exhaust radiation high or the radiation T.onitor failed.
The current design provides for bypassing the above safety act-uation signals by a single keylock switch (one for System A, one for System B).
In order to segregate the safety signals such that override of one signal may not block any other,the following modifications are proposed:
1)
Four keylock switches (two for each train) will'be installed in addition to the existing keylock.
i switches to provide segregated override switches for each of the safety actuation signals.
2)
The reactor water level' low and drywell pressure high signals wi.~
be separated by connecting the circuits to sep rate relays.
I m
6 3)
The valve closure logic will be modified so as to provide segregated override signals to each of the three safety actuation signals.
QUESTION 2.
The NRC position that sufficient physical features need to be provided to facilitate adequate administrative con-trolsa is satisfied where you have provided keylock bypass switches.
However for the reset of other ESF actuation signals, you responses b,c do not indicate that the position is satisfied.
Describe the physical features that prevent unintentional reset of the ESF actuation signals, or describe how you will modify the reset function to eliminate the design deficiency.
Provide your schedule for completion of each such modification.
RESPONSE
We have reviewed the " Override" and " Reset" controls for all ESF actuation signals and containment isolation valves.
We find that.
4 sufficient physical features have been provided to comply with NRC position pertaining to " Override" and " Reset" of safety actuation signals.
Unintentional blocking or reset of safety actuation signals and unintentional opening of a containment isolation valve (af ter s safety actuation signal has been reset) is prevented by use of the following design features:
a)
Manual override of ESF actuation signals is possible only by use of "keylock" bypass switches, with key removable in the " Normal" position only.
If a key-lock switch is selected to " Emergency-Override" position, the condition is annunicated in the plant control room.
The proposed modifications listed in response to NRC Question No. 1 above, will comply with NRC position of separate override switches for each safety actuation signal.
b)
The control logic used for Reactor Protection and containment isolation is such that ESF actuation signal trip relays (such as low reactor water level high,-
drywell pressure) must be deliberately reset by separate " reset" switches after the actuation signal has cleared.
c)
The design of the control systems _for all containment isolation valves is such that the " Resetting" or
" Override"'of the containment isolation signals will not result in automatic. reopening of these valves.
The operator must take deliberate action to open a valve after " reset" or " override" of safety actuation signal by separate control switches.
All control switches used
4 for containment isolation valves are_either momentary contact "OPEN-Neutral-CLOSE" type with spring return to neutral or maintained contact "OPEN-CLOSE" type.
Whenever spring return to neutral switches are used, the operator must deliverately turn the switch to "OPEN" position.
The valve will then open only if each of the ESF actuation signals have cleared and have been reset.
Wherever maintained "OPEN-CLOSE" switches are used and the switch is left in the main-tained "OPEN" position, the operator must first turn the switch to "CLOSE" position and then the "OPEN" position to open a valve after each of the ESF actuation signals have cleared and have been reset.
d)
There is no single inadvertent operator action that can open any Containment Isolation Valve following a LOCA.
Furthermore, no containment isolation valves open without deliberate operator action after ESF actuation signals have cleared and have been reset.
Therefore, the design of " Override" (after-the modification in response to Question No. 1 above is completed) and the " Reset" of ESF actuation signals is in ccmpliance with the NRC position and no other modification of these circuits will be necessary.
REFERENCES:
a.
NRC/DL letter (A. Schwencer) to all BWR and PWR licensees,
" Containment Purging During Normal Plant Operation,"
November 28, 1978 b.
PASNY letter, Paul J. Early, to Director of Nuclear Reactor Regulation, " Response to NRC-Request of Additional Information for the Containment Purge and Vent: System,"
March 19, 1980, JPN-80-16.
c.
PASNY letter, Paul J. Early, to Director.of Nuclear Reactor Regulation, " Justification for Continued Containment Purging During Normal Plant Operation," August 15, 1979, JPN-80-50.
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