ML20214N679
| ML20214N679 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 09/05/1986 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Zwolinski J Office of Nuclear Reactor Regulation |
| References | |
| 3866F, NUDOCS 8609160424 | |
| Download: ML20214N679 (3) | |
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GPU Nuclear Corporation
. NUOIM7 1001.1 paceParkway Parsippany. New Jersey 07054-1149 (201)263-6500 TELEX 136-482 Writer's Direct Dial Number:
September 5, 1986 Mr. John A. Zwolinski, Director BWR Project Directorate #1 Division of BWR Licensing U.S. Nuclear Regulatory Comission Washington, D.C.
20555
Dear Mr. Zwolinski:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 Rod Worth Minimizer - Request for Infomation Attached is our response to the request for additional infomation forwarded to us by letter dated July 11, 1986. The request concerned Technical Specification Change Request No.145, which proposes a temporary change to Oyster Creek Appendix A Technical Specifications to allow unlimited startups with an inoperable rod worth minimizer only during upcoming Operating Cycle 11.
If you should have any questions concerning infomation provided in the attachments, please contact Mr. M. W. Laggart at (201) 299-2341.
r ruly y urs P. E edler Vic resident and Director ter Creek PBF/PC/hef cc: Dr. Thomas E. Murley, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Resident Inspector g
Oyster Creek Nuclear Generating Station oo Forked River, NJ 08731 on mo Mr. Jack N. Donohew, Jr., Project Manager re BWR Project Director #1 ofc5 Division of Licensing jQ U.S. Nuclear Regulatory Commission l
g Phillips Building, Mail Stop 314 l
og 7920 Norfolk Avenue l
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)I m a.o-Bethesda, MD 20014 F
GPU NucMar Corporation is a subsdary of General Pubhc Utihtie Corporation I
ATTACHMENT I Request for Additional Information Rod Worth Minimizer Request It is therefore, requested (a.) that you add to the Bases of Specification 3.2 a brief statement that the operating time frame in Cycle 11 without a RWM will be kept to a minimum compatible with the changeover, (b.) that you review, and where needed, improve your procedures and related forms, physical setup and quality control to assure that the second operator provides an effective and truly independent monitoring of the control rod movements and (c.) that you provide the staff with a description of this review and resulting procedure.
Response
a.
Attachment II contains a proposed addition to the Bases of Technical Specification 3.2.
b.
A review of procedure No. 218, " Operation Below 10% Rated Power with the Rod Worth Minimizer Bypassed or Inoperable", has been made and changes will be incorporated to address the current Oyster Creek control rod withdrawal sequencing (BPWS) during startup. The procedure revision will be implemented prior to restart from the current (Cycle 11R) refueling outage. New control rod pattern templates are being fabricated to comply with BPWS. We believe that existing procedural controls governing independent monitoring of control rod movements by the second licensed operator and core engineer provide reasonable assurance that the desired control rod withdrawal sequence will be followed.
c.
The procedure has been reviewed by cognizant personnel in accordance with Technical Specifications and their implementing procedures. The procedure requires a second licensed operator to check each control rod selected by the first operator and to visually observe control rod movement indication and independently document the move on the Control Rod Schedule Master Sheet and Control Rod Group Designation Sheet. The second operator informs the first operator if he has not selected the proper control rod. A core engineer shall also verify that the proper control rod is selected and notify the operators if the proper sequence is not being followed. Both the second operator and the core engineer are required to initial the appropriate block on both forms verifying conformance to the control rod withdrawal sequence.
3866f
e 3.2-5 ATTACHMENT II l
for the entire subsequent fuel cycle. The criterion will be satisfied'by demonstrating Specification 4.2.A at the beginning of each fuel cycle with the core in the cold, xenon-free condition. The demonstration will include consideration for the calculated reactivity characteristic during the following operating cycle and the uncertainty in this calculation.
1 The control rod drive housing support restricts the outward movement of a control rod to less than 3 inches in the extremely remote event of a housing failure (2). The amount of reactivity which could be added by this small amount of rod withdrawal, which is less than a normal single withdrawal increment, will not contribute to any damage to the reactor coolant system.
The support is not required when no fuel is in the core since no nuclear consequences could occur in the absence of fuel The support ip-fot required if the reactor coolant system is at atmospheric pressure since there would then be no driving force to rapidly eject a drive housing. The support is not i
required if all control rods are fully inserted-since the reactor would remain l
subcritical even in the event of complete ej'ection of the strongest control rod (3).
The Rod Worth Minimizer (4) provides automatic supervision of conformance to the specified control rod patterns.
It serves as a back-up to procedural control of control rod worth.
In the event that the RWM is out of service i
when required, a licensed operator can manually fulfill the control rod pattern conformance functions of the RWM in which case the normal procedural controls are backed up by independent procedural controls to assure conformance during control rod withdrawal. This allowance to perform startup without the RWM is limited to once each calendar year to assure a high operability of the RWM which is preferred over procedural controls.
In anticipation of problems with the old RWM during operating Cycle 11 and the l
possibility of an unplanned shutdown and subsequent restart during operating Cycle 11 while the changeover to the new RWM is in progress with neither the old or new RdM operable, a temporary change to the Technical Specifications has been provided, for Cycle 11 only, which will allow unlimited startups with j
an inoperable RWM. Every effort will continue to be made, however, to maintain the old RWM in an operable status until the new RWM is put into service.
)
Control rod drop accident (RDA) results for plants using banked position
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withdrawal sequences (BPWS) show that in all cases the peak fuel enthalpy in an RDA would be much less than the 280 cal /gm design limit even with the maximum incremental rod worth. The BPWS is developed prior to initial
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operation of the unit following any refueling outage and the requirement that the operator follow the BPWS is supervised by the RWM or a second licensed operator.
If it is necessary to deviate slightly from the BPWS sequence (i.e., due to an inoperable control rod) no further analysis is needed if the maximum incremental rod worth in the modified sequence is 61.0% dK.
An j
incremental control rod worth of 61.0% AK will not result in a peak fuel l
enthalpy above the design limit of 280 cal /gm as documented in reference 10.
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Amendment No. 75 3866f 4
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