ML20213F460
| ML20213F460 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/07/1987 |
| From: | Bailey J WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20213F462 | List: |
| References | |
| ET-87-0178, ET-87-178, NUDOCS 8705150335 | |
| Download: ML20213F460 (8) | |
Text
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CREEK NUCLEAR OPERATING CORPORAflON May 7, 1987 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Letter: ET 87-0178 Re:
Docket No. 50-482 Subj:
Revision to Technical Specification 3.1.3.1 -
Group Height Gentlemen:
The purpose of this letter is to transmit an application for amendment to Facility Operating License No.
NPF-42 for Wolf Creek Generating Station, Unit No.
1.
This license amendment request proposes revising Technical Specification 3.1.3.1, which addresses group height of movable control assemblies.
This application for amendmer., :avises Technical Specification 3.1.3.1, Group Height, and its associated Bases to allow continued operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with one or more control rod assemblies inoperable due to electrical
/ electronic problems in the rod control system provided all affected control rods remain trippable. A complete Safety Evaluation and Significant Hazards Consideration are provided as Attachments I and II respectively.
The proposed changes to Technical Specification 3.1.3.1 and its associated Bases are provided in Attachment III.
f In accordance with 10 CFR 50.91, a copy of this application for amendment with attachments is being provided to the designated Kansas state official.
Enclosed is a check (No. 000125) for the $150.00 application fee required by 10 CFR 170.21.
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I P.O. Box 411 i Burbngton. KS 66839 / Phone- (316) 364-8831 An Equai Oppeeturwty Emdoyer M F HCN ET
ET 87-0178 Pcge 2 May 7, 1987 The proposed revision to the Wolf Creek Generating Station Technical Specifications will be fully implemented within 30 days of formel Nuclear Regulatory Commission approval.
If you have any question concerning this matter, please contact me or Mr. O. L. Maynard of my staff.
Very truly yours, 7 A1 M
/
John A. Bailey Vice-President Engineering and Technical Services JAB:Jad Enclosure Attachments:
I - Safety Evaluation II - Significant Hazards Consideration III - Proposed Technical Specification Changes cc:
P0'Connor (2)
RMartin JCummins GAllen l
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STATE OF KANSAS'
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) SS COUNTY OF COFFEY
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John A. Bailey, of lawful age, being first duly sworn upon oath says that he is Vice-President Engineering and Technical Services of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the content thereof; that he has executed that same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, I
information and belief.
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By John A. Bailey [
Vice-President hgineering an$
Technical Services SUBSCRIBED and sworn to before me this f
day of Did p, 1987.
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ATTACIDfENT I SAFETY EVALUATION i
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Attechment I to ET 87-0178 Paga 1 of 2 May 7,1987 SAFETY EVALUATION This amendment request revises Wolf Creek Generating Station (WCGS),
Unit No.
1, Technical Specification 3.1.3.1, Group Height, and its associated Bases to allow continued operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for diagnosis and repair, with one or more control rod assemblies inoperable due to a rod control urgent failure alarm or other electrical problem in the rod control system provided all affected control rods remain trippable.
Background
As described in the WCGS Updated Safety Analysis Report (USAR) the Control Rod Drive System (CRDS) serves to insert or withdraw rod cluster control assemblies within the reactor core to control average core temperature and to shut down the reactor.
The CRDS performs its intended safety function, reactor trip, by putting the reactor in a suberitical condition when a safety system setting is reached, with any assur.ed credible failure of a single active component. The essential elements of the CRDS (those required to ensure reactor trip) are isolated from nonessential portions of the CRDS (the rod control system).
The CRDS provides a Rod Control Urgent Failure alarm, which indicates that an electronic / electrical malfunction has occurred within the CRDS.
The conditions that can cause this alarm do not affect the ability to trip any control rods.
This may result in a situation where the control rods cannot be stepped in or out of the reactor, however, the rods remain trippable and therefore capable of performing their safety function.
WCGS Technical Specifications 3.1.3.1 ACTION b, currently requires that, "with more than one full-length rod inoperable or misaligned from the group step counter demand position by more than + 12 steps (indicated position),
be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />".
Although the current Technical Specification recognizes the greater significance of rods being immovable or known to be untrippable, acknowledgement of the lesser significance of electrically inoperable rods would allow additional time for diagnosis and repair of malfunctioning equipment while maintaining safe operation of WCGS.
The proposed amendment request provides a distinct ACTION statement for an inoperable rod consistent with the significance of the malfunction.
A rod that is inoperable due to being untrippable is more significant than a rod that cannot be stepped due to an electrical malfunction, but remains trippable. Distinguishing between these types of malfunctions will allow an appropriate time period to complete corrective action commensurate with the significance of the malfunction.
WCGS proposes that the existing Technical Specification be revised to allow continued operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for diagnosis and repair, with one or more control rod assemblies inoperable due to a rod control urgent failure alarm or other electrical problem in the rod control system provided all affected control rods remain trippable.
Attcch::nt I to ET 87-0178 P2ga 2 of 2 May 7, 1987 Evaluation The proposed change to allow 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> rather than 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to restore electrically inoperable control rods to operable status will not affect the probability of occurance or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the Safety Analysis Report. The inoperable control rod (s) can still be tripped and therefore is available to perform its safety function. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowance is based on engineering judgement considering the safety significance of the malfunction. Since the safety function (reactor trip) of the CRDS system is not impaired, the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time allowance was determined to be appropriate.
This change would not create the possibility for an accident or malfunction of a different type then any previously evaluated in the Safety Analysis Report.
This change reduces the burden on the control room staff, by allowing sufficient time for system repair without the concurrent task of conducting an orderly plant shutdown.
This change also minimizes the potential for a hurried diagnosis which could result in human error and unnecessary transients.
This change does not affect the margin of safety as defined in the basis for any technical specification.
The control rods remain trippable and are available to assure adequate shutdown margin.
Conclusion Based on the above discussions and the considerations presented in Attachment II, the proposed revisions to Technical Specification 3/4.1.3 and its associated bases do not increase the probability of occurence or the consequences of an accident of malfunction of equipment important to safety previously evaluated in the safety analysis report; or create a possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report; or reduce the margin of safety as defined in the basis for any technical specification.
There fore, the proposed revisions do not adversely affect or endanger the health or safety of the general public or involve a significant safety hazard.
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ATTACHMENT II SIGNIFICANT HAZARDS CONSIDERATION i
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Attrchment II to ET 87-0178 Paga 1 of 1 May 7,1987 SIGNIFICANT RAZARDS CONSIDERATION This amendment request revises Wolf Creek Generating Station (WCGS),
Unit No.
1, Technical Specification 3.1.3.1, Group Height, and its associated Bases to allow continued operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for diagnosis and repair, with one or more control rod assemblies inoperable due to a rod control urgent failure alarm or other electrical problem in the rod control systen provided all affected control rods remain trippable.
1.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
Increasing the allowed outage time associated with electronic / electrical malfunctions of the Control Rod Drive System (CRDS) is acceptable, since the safety function of the CRDS (reactor trip) remains unaffected.
The conclusions in the Updated Safety Analysis Report (USAR) remain valid.
The proposed change does not affect the ability of the CP.DS to perform its intended safety function, reactor trip, by putting the reactor in a suboritical condition when a safety system setting is reached. The design of the CRDS assures isolation of essential elements of the CRDS (those required to insure reactor trip) from nonessential portions of the CRDS.
2.
The proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated.
There are no new failure modes or mechanisms associated with the proposed change.
This change does not involve any modification in the operational limits or physical design of the involved systems. The change merely allows an extended time period for the diagnosis and repair of portions of the CRDS, these reducing the probability of a plant transient because of insufficient time for proper corrective action or a hurried diagnosis.
3.
The proposed change does not involve a significant reduction in a margin of safety.
This change does not affect any Technical Specification margin of safety.
This change allows appropriate ACTIONS commensurate with the significance of the CRDS malfunction, while not requiring plant transients in response to malfunctions that do not affect the capability of the CRDS to perform its safety function.
Based on the above discussions and those presented in Attachment I, it has been determined that the requested Technical Specification revisions do not involve a significant increase in the probability or consequences of an accident or other adverse condition over previous evaluations; or create the possibility of a new or different kind of accident or condition over previous evaluations; or involve a significant reduction in a margin of safety.
Therefore, the requested license amendment does not involve a significant hazards consideration.
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