ML20138C728
| ML20138C728 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 10/16/1985 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20138C733 | List: |
| References | |
| ULNRC-1174, NUDOCS 8510230020 | |
| Download: ML20138C728 (8) | |
Text
UNION ELECTRIC COMPANY 1901 Grotot Street St. Louis Donold F. Schnell October 16, 1985 Mr. Harold R..Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555 ULNRC-1174
Dear Mr. Denton:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 REVISION TO TECHNICAL SPECIFICATION 3/4.3.1 REACTOR TRIP SYSTEM INSTRUMENTATION Union Electric herewith transmits three (3) original and forty (40) conformed copies of an application for amendment to Facility Operating License No. NPF-30 for Callaway Plant, Unit 1.
This application requests that Section 3/4.3.1, Reactor Trip System Instrumentation, of the Callaway Plant Technical Specifi-cations, Appendix A to the Operating License, be revised.
The requested change revises the present Technical Specification regarding specified surveillance intervals and out-of-service times for the Reactor Protection System Instrumentation.
The revision is based on implementation of changes approved generically as a result of the NRC's review of WCAP-10271 and Supplement 1, with the exception that bypass testing is not being requested as discussed in the attached Safety Evaluation and Significant Hazards Consideration.
Enclosed is a check for the $150.00 application fee required by 10 CFR 170.21.
Very truly
- ours, C510230020 851016
..N O PDR ADOCK 05000483 A
RAP /drs
Enclosures:
. 1 - Safety Evaluation 2 - Significant Hazards Consideration
)1 3 - Marked Specification Pages 3/4 3-1 thru 3-12 and I
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B 3/4 3-1 thru 3-3 Ig y N igel b gb W
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STATE OF MISSOURI )
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Robert J. Schukai, of lawful age, being first duly sworn upon oath says that he is General Manager-Engineering (Nuclear) for 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 Rob rt J.
c ukai i
Gener ager-Engineering Nuclear SUBSCRIBED and sworn to before me this /6 day of M, 1985'
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BARDAPA PFAFF NOT/JtY PU3ttC. STATE 07 MIS 50Um MY C0:4:4tSS10N EXP!RES APRIL 22, 1983 ST. LOUI3 COUNTY.
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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 SNUPPS 5 Choke Cherry Road Rockville, Maryland 20850 G. C. Wright 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 RRil Steedman, Missouri 65077 Tom Alexion Of fice of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission Mail Stop P-31r.
7920 Norfolk Avenue Bethesda, MD 2001' Ron Kucera, Deputy Director Department of Natural Resources P.O. Box 176 Jefferson City, Missouri 65102 i
ULNRC-Il74 Page 1 of 2 SAFITY EVALUATION The Safety Evaluation for this request is documented in WCAP-10271 and Supplement I and approved 'in the SER dated February 21, 1985 by the NRC.
This technical specification revision request is based on implementation of changes approved generically as a result of the NRC's review of WCAP-10271 and Supplement 1.
Proposed Chances Revisions to Callaway Plant Reactor Protection System (RPS)
Instrumentation Technical Specifications are based on WCAP 10271 and its Supplement I and are proposed as follows:
1.
Increase the surveillance interval for RPS analog channel operational tests from once per month to once per quarter, 2.
Increase the time during which an inoperable RPS analog channel may be maintained in an untripped condition from one hour to six
- hours, 3.
Increase the time an inoperable RPS analog channel may be bypassed to allow testing of another channel in the same function from two hours to four hours.
The Callaway design does not currently include the capability for bypass testing. Therefore, the portion of WCAP 10271 and its Supplement '
1, which concern bypass testing are not applicable to this amendment request and Significant Hazard Evaluation.
The following is Union Electric's rasponse to the conditions imposed by the NRC to allow implementation of these changes:
1.
The use of a staggered test plan for the RPS channels changed to the quarterly test frequency.
Union Electric has incorporated the staggered test plan requirement into the Technical Specification revision.
2.
Plant procedures require a common mode evaluation for failure in the RPS channels changed to the quarterly test frequency and additional testing for plausible common cause failures.
Union Electric will implement procedures to address evaluation of and required actions associated with plausible common cause problems at the time quarterly tecting goes into effect.
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ULNRC-Il74 Page 2 of 2 3.
Installation of hardware to incorporate the capability of testing in bypass mode.
Union Electric does not have this capability; therefore, bypass testing is not addressed in this change.
4.
For channels that provide input to both the RPS and the Engineered Safety Feature Actuation System (ESFAS), cautionary notes in the RPS tables should refer to the more stringent ESFAS requirements.
Union Electric has included caution statements in the
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technical specification revision as part of action state-ments referencing the more stringent requirements for the ESFAS channels.
5.
Setpoint drift.
Union Electric will collect the "as found" and "as left" data for each channel over a one year period after quarterly testing has begun.and will~ make changes to the setpoints and allowable values, as necessary, af ter the data has been reviewed.
ULNRC-1174 Page 1 of 3 SIGNIFICANT HAZARDS CONSIDERATION Significant Hazards Consideration Analysis - Pursuant to 10 CFR r
50.91 and 10 CFR 50.92 For The Proposed Amendment to Callaway Plant L
Reactor Protection System Instrumentation Technical Specifications.
Proposed Changes Revisions to Callaway Plant Reactor Protection System (RPS)
Instrumentation Technical Specifications are based on WCAP 10271 and its supplement I and are proposed as follows:
1.
Increase the surveillance interval for RPS analog channel operard.onal tests from once per month to once per quarter, 2.
Increase the time during which an inoperable RPS analog channel may be maintained in an untripped condition from one hour to six
- hours, l
3.
Increase the time an inoperable RPS analog channel may be bypassed to allow testing of another channel in the same function from two hours to four hours.
The Callaway design does not currently include the capability for bypass testing. Therefore, the portion of WCAP 10271 and its Supplement 1, which concern bypass testing are not applicable to this amendment request and Significant Hazard Evaluation.
Analysis Callaway Plant has reviewed the requirements of 10 CFR 50.92 as they relate to the proposed RPS technical specification changes for the Callaway Plant and determined that a significant hazards consideration is.not involved.
In support of this conclusion, the following analysis is provided.
Criterion 1 - Operation of Callaway Plant in accordance with the proposed license amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.
Implementation of the proposed changes is expected to result in an acceptable increase in total Reactor Protection System yearly unavailability. This increase, which is primarily due to less frequent-surveillance, results in an increase of similar magnitude in the probability of an Anticipated Transient Without Trip (ATWT) and in the probability of core melt resulting from an AfWT.
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Implemention of the proposed. changes is expected to result in a significant reduction in the probability of core melt from inadvertent reactor trips. This is a result of a reduction in the number of
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-inadvertent reactor trips occurring during testing of RPS instrumentation. This reduction is attributable to less frequent l
surveillance testing.
The reduction in core melt probability due to inadvertent reactor j
trip is sufficiently large to counter the increase in ATWT core melt probability resulting in an overall reduction in total core melt i
I probability.
The proposed changes do not result in an increase in the severity I
or consequences of an accident previously evaluated.
Implementation of j
the proposed changes affects the probability of failure of the RPS but does not alter the manner in which protection is afforded nor the manner t
in which limiting criteria are established.
Criterion 2 - The proposed license amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.
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The proposed changes do not result in a change in the manner in i
which the Reactor Protection System provides plant protection. No
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change is being made which altera the functioning of the Reactor Protection System -(other than in a test mode). Rather, the likelihood l
1 or probability of the Reactor Protection System functioning properly is affected as described above..Therefore, the proposed changes do not l
create the possibility of a new or different kind of accident nor I
l involve a reduction in a margin of safety as defined in the Safety l
Analysis Report, j
i The proposed changes do not involve hardware changes.
(Callaway i
does not currently have full capability for bypass testing. Union j
Electric may elect to implement future design changes to take advantage of the test in bypass feature.)
Some existing instrumentation is j
designed to be tested in bypass and current technical specifications l
allow testing in bypass. Testing in bypass is also recognized by IEEE Standards.
i Criterion 3 - The proposed license amendment does not involve a l
significant reduction in a margin of safety.
The proposed changer do not alter the manner in which safety limits, limiting safety system setpoints;or limiting conditions'for
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operation are determined. The impact of reduced testing other than as i
addressed above is to allow a longer time interval over which instrument l
l uncertainties (e.g., drifri may act.
Experience at two Westinghouse plants with extended surveillance intervals has shown the initial f
uncertainty assumptions to be valid for reduced testing.
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Implementation of the proposed changes is expected to result in an overall improvement in safety by:
a.
Fewer inadvertent reactor trips per unit per year. This is due to less frequent testing which minimizes the time spent in a partial trip condition.
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Higher quality repairs leading to improved equipment reliability
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due to longer repair times.
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Improvements in the effectiveness of the operating staff in monitoring and controlling plant operation. This is due to less frequent distraction of the operator and shift supervisor to
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attend to instrumentation testing.
t Example 10 CFR 50 - Statements of Consideration contains, "r smples of Amendments that are Considered Not Likely to Involve Significant Hazards Considerations." One of the examples provided is:
(vi) A change which either may result in some increase to the probability or consequences of a previously-analyzed accident or may reduce in some way a safety margin, but where the results of the change are clearly within all acceptable criteria with respect to the system or component specified in the Standard Review Plan:
for example, a change resulting from the application of a small refinement of a previously
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used calculational model or design method.
As previously stated implementation of the proposed changes results in an acceptable increase in the probability of ATWT and ATWT core melt.
Overall core melt probability decreases.
Implementation of the proposed changes does not increase the consequences of a previously analyzed accident nor reduce a margin of safety. Functioning of the RPS and the manner in which limiting criteria is established is unaffected. The stated example of a change which is likely not to involve a significant hazards consideration is applicable therefore to the proposed changes.
Conclusion t
The foregoing analysis demonstrates that the proposed amendment to Callaway Plant technical specifications does not involve a significant increase in the probability or consequences of a previously evaluated accident, does not create the possibility of a new or different kind of accident and does not involve a significant reduction in a margin of safety. Additionally' fewer inadvertent reactor trips are expected, equipment reliability is expected to increase and operator effectiveness is expected to improve.
Based upon the preceding analysis, Callaway Plant concludes that the proposed amendment does not involve a significant hazards consideration.
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