ML20217G710
| ML20217G710 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 10/07/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217G707 | List: |
| References | |
| NUDOCS 9710140168 | |
| Download: ML20217G710 (6) | |
Text
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i UNITED STATES B
NUCLEAR REGULATORY COMMISSION Nf WASHINGTON, D.C. SoHH001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.112 TO FEILITY OPERATING LICENSE NO. NPF-42 WOLF CREEK NUCLEAR OPERATING CORPORATION WQLF CREEK GENERATING STATION DOCKET N0. 50 482
1.0 INTRODUCTION
i By letter dated September 6.1997, Wolf Creek Nuclear Operating Corporation l
(the licensee) requested changes to the Technical Specifications (Appendix A to Facility Operating License No. NPF-42) for the Wolf Creek Generating Station. The proposed changes would add a footnote to Technical Specification
(
Surveillance Requirements 4.8.1.1.2.g.2)c)2). 4.8,1,1.2.g.3)d) and 4.8.1.1.2.g.4)d). This footnote would (1) allow one-time testing of the i
blocking / time delay contacts associated with relays K1102, K4102, K1117.
K4117. K1118, and K4118, at power, and (2) extend the provisions of Technical Specification 4.0.3 to complete testing within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, to permit completion of the testing of these contacts by 1906 hours0.0221 days <br />0.529 hours <br />0.00315 weeks <br />7.25233e-4 months <br /> on September 6, 1997.
I
2.0 BACKGROUND
On September 4.1997, as a result of reviews undertaken in response to Generic Letter 96-01. " Testing of Safety Related Logic Circuits," and information received from another plant, Wolf Creek Nuclear Operating Corporation (WCNOC) determined that the existing surveillance testing procedures did not completely verify the operation of certain contacts in the emergency diesel generator sequencer.
Specifically, it was discovered that certain relay contacts required to open have not been tested during performance of surveillance procedure STS KJ-001A/B, " Integrated Diesel Generator Safeguards Actuation Test Train A/B." The contacts in K1102 K4102, K1117. K4117. K1118 and K4118. question are actuated by relays The current testing process, implemented through STS KJ-001A/B, has not demonstrated the function of the contacts because there are other contacts in series that could also be open during the testing.
These relay contacts provide a blocking / time delay function for start of the component cooling water (CCW) pumps, essential service water (ESW) pumps, and the motor driven auxiliary feedwater (MDAFW) pumps. On a loss of offsite power, the CCW, ESW. and MDAFW pumas are shed from the safety busses and then loaded in sequence to the EDGs. T1e relay contacts' blocking / time delay ok Soo $ o oOO a2 P
PDR m
9 2-function ensure that no matter what the start demand is for the pumps, they are not started until the parallel contacts of the load sequencer close to start the pump at the required time increment.
Technical Specification 4.0.3 was entered at 1906 CDT on September 4,1997, due to the discovery that the contacts had not been adequately tested in accordance with the technical specification surveillance requirements.
Technical Specification 4.0.3 allows the ACTION requirements of the applicable sections to be delayed for u) to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to permit the completion of the surveillance when the allowaale outage time limits of the ACTION requirements are less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
However. Technical Specification 4.8.1.1.2.g requires that the surveillance testing be performed once every 18 months during shutdown. Thus, these surveillances cannot be performed at power under the current technical specification requirements.
Therefore. "CNOC requested Enfnrcement Discretion on September 5. 1997, to permit one-time testing of these contacts while the plant is at power. WCN0C also requested an additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, beyond the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> aermitted by Technical Specification 4.0.3 to comalete this testing. T11s request was.
verbally granted by the NRC on Septem)er 5. 1997 and followed with a letter dated September 12. 1997, 3.0 EVALUATION The standby power supply for each safety-related load group consists of one diesel generator, mplete with its accessories and fuel storage and transfer systems. The stanooy power supply is capable of supplying essential loads recessary to reliably and safely shut down and isolate the reactor. The d esel generator loads are determined on the basis of nameplate rating, pump pressure and flow conditions, or pump runout conditions.
The continuous rating of the diesel generator is based on the maximum total load required at any time. The load shedding and emergency load sequencing (NF) system removes selected loads from the Class 1E busses under degraded bus voltage conditions, or upon the presence of a safety injection signal, and actuates equipment fed from these busses in a predetermined sequence following degraded bus voltage conditions or in the presence of a loss-of-coolant accident (LOCA).
The load shedding portion of the NF system removes selected loads under degraded voltage conditions on the 4160 volt Class IE busses.
Loads are then actuated in programed intervals by the sequencing portion of the system such that the voltage of the busses does not fall below 75 percent of rated voltage and the frequency does not fall below 95 percent of rated frequency.
The contacts in question are actuated by relays K1102. K4102. K1117. K4117.
K1118 and K4118. The relay contacts orovide a blo: king / time delay function for starting of the CCW. ESW. and MDA W pumps. On a loss of offsite power, the CCW. ESW. and MDAFW pumas are shed from the safety busses and then loaded in secuence to the EDGs. T1ese contacts ensure that no matter what the start demanc is for the pumas, they are not started until the required time increment elapses. T11s prevents the simultaneous starting of pumps that l
3-could lead to a degraded bus voltage condition, causing the sequence (shedding and reloading) to be repeated.
The integrated EDG and engineered safety features actuation test is performed during shutdown because of a potential that this surveillance could cause perturbations to the electrical distribution systems that could challenge continued steady state operation and unit safety systems.
The licensee has proposed to perform only a partial test of the subject load shedding and emergency load sequencing system relay contacts while at power. This test does not duplicate the integr' ad EDG and engineered safety features actuation test and will not cause any,.rturbation to the electrical distribution systems that could challenge steady state o,neration or unit safety systems.
For the relay contacts associated with the ESW and CCW pumps, the licensee has proposed to test the contacts by actuating slave relay K645A/B and verifying that the blocking contact on relays K1117. K4117. K1118 and K4118 change state. The licensee has stated that testing of these contacts at )ower will be performed in accordance with specific procedures approved for tais purpose.
For the relay contacts associated with the MDAFW pumps, the licensee has proposed to test the contacts by isolating the relays (K1102. K4102) from their normal power supply by lifting leads, and actuating the relay using a portable power source to verify the contacts change state for the specified time period.
During the test for the "A" MDAFW oump the leads from relay K1102 that shed NB0112. NB01 Normal Feeder Breater." must be lifted to preclude tripping this breaker.
Improper conduct of the test could result in trigning NB0112. "NB01 Normal Feeder Breaker.' However, any effects would be mitigated by implementation of existing plant off-normal procedures.
The licensee has stated that this activity will be administrative 1y controlled to ensure removal and restoration are safely accomplished.
During the testing the licensee has committed to the following compensatory actions:
1.
WCNOC will follow its protected train philosophy and only one train will be worked on at a time.
2.
No work will be ongoing in the switchyard: System Operations will be notified to maintain maximum grid stability.
Testing these relays at power will not cause any degradation in system performance, nor will it increase the number of challenges to equipment assumed to function during an accident situation. The testing will require related equipment to be declared inoperable for the duration of each test, but these durations will be much less than those allowed by the applicable technical specification action statements.
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. The additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> requested by the licensee to perform the testing of the contacts is necessary to allow sufficient time to prepare for and execute the testing. This additional time (48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> total) is less than the allowed outage time for one EDG inoperable (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />).
Based on the above, the staff corcludes that the one time testing of the blocking / time delay contacts associated with relays K1102, K4102, K1117, K4117. K1118, and K4118, at power, and the extension of the provisions of
~ Technical Specification 4.0.3 to complete testing within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, to permit completion of the testing of these contacts by 1906 hours0.0221 days <br />0.529 hours <br />0.00315 weeks <br />7.25233e-4 months <br /> on 4
september 6, 1997, is acceptable.
4.0 EXIGENTCIRCUMSTANCES The Comission's regulations,10 CFR 50.91. contain provisions for issuance of amendments when the usual 30-day public notice period cannot be met.
One type of special exception is an exigency.
An exigency is a case where prompt action is required (before the expiration of a 30-day comment period),
Under such circumstances, the Commission notifies the public in one of two ways: by issuing a Federal Reaister notice providing an opportunity for hearing and allowing at least two weeks for prior public comments, or by issuing a press release discussing the proposed changes, using the local media.
In this case, the Commission used the first approach.
The exigent circumstances for this TS amendment request exist due to the recent discovery that certain contacts in the emergency diesel generator sequencer had not oeen monitored for aroper operation during the required surveillance tests. The TS require tie surveillance tests to be performed with the plant shut down and the additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is needed to provide adequate time to perform the tests. This amendment will allow the testing of the contacts with the plant at power, thus avoiding a plant shutdown.-
Processing this TS amendment request on an exigent basis also ends the need for the Notice of Enforcement Discretion issued by the staff on September 12, 1997.
The NRC staff has reviewed the circumstances surrounding the amendment request and finds that the circumstances could not have been avoided and the licensee made a timely request for the amendment. Therefore, the staff finds that the license amendment may be issued in an exigent manner pursuant to 10 CFR 50.91(a)(6).
There were no public comments in response to the notice published in the Federal Reoister.
5.0 BASIS FOR FINAL NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION The Commission's regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant hazards considerations if operation of the fccility in accordance with the
. amendment would not (1) involve a significant increase in the probability of consequences of an accident previously evaluated: or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
1.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
This proposed change does not change the function or performance requirements for the load shedding and emergency load sequencing system, as described in the Updated Safety Analysis Report (USAR) and the technical specifications. Testing these relays at power will not cause any degradation in system performance, nor will it increase the number of challenges to equipment assumed to function during an accident situation.
The testing will require related equipment to be declared inoperable for the duration of each test, but these durations will be much less than those allowed by the ap>l1 cable technical specification action statements.
Further, t1e proposed change would revent an unnecessary unit shutdown which could result in a reactor transient and a unwarranted challenge of the safety-related systems. This is a one-time test, and j
future testing will be performed in accordance with the requirements specified in the technical specifications.
Thus, the proposed change will not result in an increase in the consequences of, or an increase in the probability of occurrence of any accident previously evaluated.
2.
The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
The load shedding and emergency load sequencing system will continue to perform in a manner consistent with the assumptions in the USAR.
No new scenarios, transient precursors. failure mechanisms, or limiting single failures are introduced. There will be no adverse effects or challenges imposed on any safety-related system as a result of this request.
Therefore, the possibility of a new or different kind of accident is not created.
3.
The proposed change does not involve a significant reduction in a margin of safety.
The purpose of this request is to allow WCNOC the ability to perform a one-time partial test of the subject load shedding and emer'ency load sequencing system relay contacts while at power.
This tes ng will demonstrate complete compliance with Technical Specification 3/4.8.1 without having to shut down the unit. This activity will not affect any system or component setpoints or safety limit settings associated with the load shedding and emergency load sequencing system.
No new accident scenarios, transient precursors, failure mechanisms, or limiting single
. failures are introduced. There will be no significant adverse effects or challenges impused on any safety-related system as a result of this request. This request will not result in a significant reduction in the margin of safety.
Based u)on the above considerations the staff concludes that the amendment meets tie three criteria of 10 CFR 50.92.
Therefore, the staff has made a final determination that the proposed amendment does not involve a significant hazards consideration.
6.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Kansas State Official was notified of the proposed issuance of the amendment. The State official had no comments.
7.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a surveillance requirement. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no signif! cant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (62 FR 49261). Accordingly, the amendment meets the eligibility criteria for-categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
8,0 CONCLUSION The Commission has concluded. based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner. (2) such activities will be conducted in compliance with the Commission's regulations.
and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: James Stone Date:
October 7, 1997
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