U-602316, Application for Amend to License NPF-62,requesting Enforcement Discretion by NRC Re TS Requirement for Accelerated Testing of Standby Emergency Diesel Generators
| ML20072C115 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 08/05/1994 |
| From: | Jackie Cook ILLINOIS POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20072C118 | List: |
| References | |
| U-602316, NUDOCS 9408170087 | |
| Download: ML20072C115 (16) | |
Text
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lif.nois Power Company Chnton Power Station P O Box 678
' Chnton. IL 61727 Tel 217 935-8881 ELLIN9IS u-60mc PROWER M7-94(08 -05 )LP 8E.100a August 5, 1994 Docket No. 50-461 10CFR2, Appendix C 10CFR50.90 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Request for Enforcement Discretion Regarding Technical Specification Requirement for Accelerated Testing of the Division 1 Diesel G_enerator
Dear Sir:
Events have occurred at Clinton Power Station (CPS) which require your prompt attention as Illinois Power (IP) requests enforcement discretion by the NRC (in accordance with 10CFR2, Appendix C) regarding the Technical Specification requirement for accelerated testing of standby emergency diesel generators when a certain number of valid test failures are experienced. CPS Technical Specification Table 4.8.1.1.2-1 requires the testing frequency for a diesel generator to be increased from at least once per 31 days to at least once per seven days when the number of failures is greater than or equal to five in the last 100 valid tests or two in the last 20 valid tests. In light of a recent failure of the Division 1 diesel generator (DGI A) undervoltage relay, which has caused testing to be accelerated in accordance with this requirement, IP is asking that this requirement for weekly testing ofDGl A be waived as IP does not believe that the recently identified failure and the corrective action taken in response to the failure warrant weekly testing of the diesel.
On July 12,1994, during a routine tour of plant equipment at CPS, an operator observed targets showing in the DGl A A-B phase and B-C phase undervoltage relays (Westinghouse model CV-2) associated with the diesel generator output breaker control circuitry. This indicated that a circuit malfunction had occurred. An investigation of this condition determined that the B-C phase CV-2 relay telephone coil had failed due to excessive current as a result of an incorrectly sized current-limiting resistor in the telephone coil circuitry. This event was considered a valid failure of DGl A since failure of either of these relays, which are part of the permissive-to-close circuitry for the DGl A output breaker, would allow premature closure of the breaker upon receipt of an automatic start signal due to or coincident with a loss of offsite power. A similar failure previously occurred on June 7,1994. In addition, it is now believed that a failure which occurred on August 3,1993 (also due to a CV-2 relay failure) was also the result of the same condition (i.e., an improperly sized current-limiting resistor).
9408170087 940805 PDR ADOCK 05000461 i P PDR h()i
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U-602316 Page 2 t
As the discovered failure of the telephone coil on July 12,1994 is believed to be a valid failure of DGl A, this event constitutes the eighth valid failure in the last 100 valid tests and the second valid failure in the last 20 valid tests for DGI A. In accordance with CPS Technical Specification Table 4.8.1.1.2-1, DGl A is now required to be tested on a weekly basis until seven consecutive failure-free demands have been performed and the number of failures is less than or equal to one in the last 20 valid tests. Assuming there are no further failures, this will require at least 9 more weekly tests to be performed on DGI A before the normal, monthly test frequency can be resumed. Because of the nature of this failure and the corrective actions taken as a result, as well as the fact that the testing required by Technical Specification Table 4.8.1.1.2-1 does not confirm proper operation of the CV-2 relay, IP believes that continued weekly testing is unwarranted.
In addition to requesting enforcement discretion, and in order to provide long-term relief from the weekly testing requirement due to the two recent failures of the DGI A CV-2 relays, IP is requesting a change to CPS Technical Specification 3/4.8.1, "AC Sources-Operating." Specifically, IP proposes to revise the "*" footnote to Technical Specification Table 4.8.1.1.2-1 to exclude the August 3,1993; June 7,1994; and July 12, 1994 DGl A valid test failures from the total number of failures used to determine the diesel generator test frequency. IP respectfully requests NRC review of this proposed change on an expedited basis so that, if approved, the license amendment can be made effective as soon as possible.
I In support ofIP's request for enforcement discretion, a more detailed description of the condition, including the circumstances surrounding the event, an evaluation of the safety significance, justification for this request and a discussion of why this request does not involve a significant hazards consideration or irreversible environmental consequences <
is provided in Attachment 2 of this letter. For the proposed Technical Specification l change, a description and the associated justification (including a Basis For No Significant IIazards Consideration) are provided in Attachment 3. A marked-up copy of the applicable page from the current Technical Specifications is provided in Attachment 4. In addition, the associated change to IP's previous request to adopt the Improved Standard .
Technical Specifications (reference IP letter U-602196 dated October 26,1993) is !
provided in Attachment 5. Funher, an aflidavit supporting the facts set forth in this proposed change to the Technical Specifications is provided in Attachment 1.
1 This request has been reviewed and approved by the CPS Facility Review Group.
Sincerely yours,
$AQAM)
.G. Cook Vice President TAB /csm Attachments
- U-602316 Page 3 cc: NRC Clinton Licensing Project Manager NRC Resident Oflice, V-690 Illinois Department of Nuclear Safety Regional Administrator, Region 111, USNRC I
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i Attachment I !
to U-602316 I 1
i J. A. Miller, being first duly sworn, deposes and says: That he is Manager of the Illinois Power Nuclear Station Engineering Department and has been duly authorized to submit this application for amendment of Facility Operating License NPF-62; that the application for amendment of Facility Operating License NPF-62 has been prepared under his supervision and direction; that he knows the contents thereof; and that to the best of his knowledge and belief said letter and the facts contained therein are true and correct.
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Date: This 5 day of August 1994.
r Signed: LXfAvGtd.ve) h J. A Miller l
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M COUNTY J Subscribed and sworn to before me this 6 day of August 1994.
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. Attachment 2 to U-602316 Page 1 of 6 REOUEST FOR ENFORCEMENT DISCRETION Requirements CPS Technical Specification Table 4.8.1.1.2-1 requires the testing frequency for a diesel generator to be increased from at least once per 31 days to at least once per seven days when the number of failures is greater than or equal to five in the last 100 valid tests or two in the last 20 valid tests. The weekly test frequency must be maintained until seven consecutive failure-free demands have been performed and the number of failures in the last 20 valid demands has been reduced to less than or equal to one.
Circumstances At 0110 hours0.00127 days <br />0.0306 hours <br />1.818783e-4 weeks <br />4.1855e-5 months <br /> on July 12,1994, IP determined that a valid failure of the Division 1 emergency diesel generator (DG1 A) had occurred. During a routine tour of plant equipment at CPS, an operator observed relay targets showing in the DGI A A-B phase and B-C phase undervoltage relays (Westinghouse model CV-2), indicating a circuit malfunction had occurred. Although the emergency diesel generator (EDG) was in its normal standby mode at the time the targets were observed, in accordance with the guidance of Regulatory Guide 1.108, " Periodic Testing Of Diesel Generator Units Used As Onsite Electric Power Systems At Nuclear Power Plants," this event was considered a valid failure of the EDG since failure of either of these relays, which are part of the permissive-to-close circuitry for the DGI A output breaker, would allow premature closure of the breaker upon receipt of an automatic start signal due to or coincident with a loss of offsite power.
An investigation of this issue determined that the B-C phase CV-2 relay telephone coil had failed (open-circuited) due to excessive current. This efTectively tripped and sealed-in the logic involving both the A-B and B-C phase relays, thus causing the targets to drop for both relays. The CV-2 relays (i.e., either relay) prevent EDG output breaker closure when the EDG output voltage is less than the EDG rated voltage. (The telephone coil associated with each relay is normally energized and becomes deenergized when the EDG reaches rated voltage.) In the event of a loss of offsite power (LOOP) or a LOOP coincident with a loss of coolant accident (LOCA), a failed telephone coil would allow the EDG output breaker to close before the EDG reaches rated voltage. Premature closure of the breaker would likely cause the generator to start too slowly relative to the start time assumed in the accident analyses. As a result, DGI A was declared inoperable in response to the identified failure of the telephone coil.
The defect which resulted in the excessive current was found to be in the telephone coil current-limiting resistor. The resistor was found to have a lower resistance value than the value implied in the manufacturer's literature. The manufacturer's literature implies that
. Attachment 2 to U-602316 l Page 2 of 6 the resistor is 2500 ohms, whereas a 1320-ohm resistor was found to be installed in the telephone coil that failed at CPS. Discussions with the manufacturer indicated that the resistor design had intentionally been changed to the smaller size, however, IP was not made aware of the change. Use of a larger resistance was subsequently discussed with the vendor.
It should be noted on June 7,1994, a similar failure (also identified by operator observation of relay targets) occurred with the other Division 1 EDG CV-2 relay (i.e., the A-B phase). That failure was docur..ented in a special report (IP letter U-602308) submitted July 7,1994. As a result of that failure, DGl A was being tested on a weekly basis at the time the July 12 failure was identified. IP has determined that the previous failure and the failure described above were both the result of the incorrectly sized telephone coil current-limiting resistor. IP has also determined this condition to be potentially reportable under the provisions of 10CFR21. (See IP's Part 21 notification, IP letter U-602305 dated June 27,1994.)
As the discovered failure of the telephone coil is considered a valid failure of DGl A, this event constitutes the eighth valid failure in the last 100 valid tests and the second valid failure in the last 20 valid tests for DGI A. In accordance with CPS Technical Specification Table 4.8.1.1.2-1, DGl A is now required to be tested on a weekly basis until seven consecutive failure-free demands have been performed and the number of failures is less than or equal to one in the last 20 valid tests. Assuming there are no further failures, at least 9 more weekly tests are required before the monthly test frequency can be resumed. As further discussed below, IP believes that continued weekly testing is unwarranted and prompt action is therefore being requested at this time to provide relief from the required weekly testing of DGI A.
Compensatory Actions Taken In response to the June 7,1994 CV-2 relay failure, IP ir.itiated development of a design change to modify the Division 1 and 2 EDG CV-2 relays. The design change was initiated to correct the excessive current condition in the CV-2 relays by replacing the 1320-ohm resistor with a resistor properly sized for the application. IP performed a calculation to determine the proper size of resistor needed to preclude failures of the telephone coil due to excessive current. It was determined that a 4000-ohm resistor was required.
Replacement parts (i.e., telephone coils and resistors) for implementing the design change had been ordered and receipt of the parts was pending at the time the July 12 failure occurred. Following the CV-2 relay failure on July 12 and after receipt of the replacement parts on July 13, IP promptly implemented the design change for both the Division 1 and Division 2 diesel generators. IP first replaced both CV-2 relays in DGI A with modified relays. For each relay, the telephone coil was replaced with a new coil and the 1320-ohm resistor was replaced with a 4000-ohm resistor. The Division 1 EDG was subsequently
- declared operable on July 13,1994. The two comparable relays associated with the 1
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Division 2 diesel generator were then also replaced with relays that had been modified in l the same manner as Division 1. The Division 2 relays were replaced and the diesel generator was returned to service on July 14,1994.
Prior to declaring the Division 1 and 2 EDGs operable following the relay modification, design-basis testing was performed to verify correct operation of the modified relays. The first test required application of the minimum DC voltage expected at the CV-2 relay to confirm the telephone coil would energize (pick-up). This was confirmed for each of the Division I and Division 2 modified relays. In addition, it was also confirmed that the telephone coil would de-energize (drop-out) at a voltage less than the pick-up voltage.
The final test performed required the application of the maximum DC voltage expected at the CV-2 relay to measure the corresponding current through the telephone coil. IP ified that the current through the Division 1 and Division 2 telephone coils was less
..an the maximum continuous current carrying capability of the coil to preclude coil burnout.
On August 3,1993, a DGl A CV-2 relay failure occurred. At that time IP believed the failure to be age related. However, IP now suspects that the failure was also the result of an incorrectly sized telephone coil current-limiting resistor. As part of the action plan developed following the August 3,1993 failure, IP verified that the same-type relays are not used in the Division 3 diesel generator. Therefore, the previously described design l change was not required to be implemented for the Division 3 diesel generator. In addition, following the August 3,1993 failure IP also confirmed that the remaining Westinghouse safety-related relays that contain telephone coils at CPS either do not use the telephone coil, are of a different design than the CV-2 relay or are normally de- l energized. Therefore, similar failures are not expected for these coils.
Justification for Req.uest As noted above, Technical Specification Table 4.8.1.1.2-1 requires the test frequency for a ;
diesel generator to be increased from monthly to weekly if the diesel generator has experienced two or more failures in the last 20 valid tests or five or more failures in the i
last 100 valid tests. This requirement for increased testing is based upon maintaining a l
target reliability for each diesel generator unit and provides a timely response to the l possibility of abrupt diesel generator degradation.
With respect to the CV-2 relay failure and the ability ofincreased testing to confirm EDG reliability following such a failure, it should be noted that failure of the CV-2 relay / telephone coil cannot be revealed by the routine surveillance testing required by Technical Specification Table 4.8.1.1.2-1. As noted previously, the basis for the accelerated testing required by the Technial Specification table is to verify diesel generator reliability. The required testing is performed in accordance with Technical Specifications 4.8.1.1.2.a.4 and 5. This testing demonstrates the capability of the EDG to
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. Attachment 2 to U-602316 Page 4 of 6 start, reach rated speed, voltage, and frequency within the required time, and remain synchronized at the rated load. However, automatic operation of the output breaker under LOOP or LOOP /LOCA conditions is only tested, and consequently a failure would only be identified, during the LOOP and LOOP /LOCA tests performed every 18 months during shutdown in accordance with Technical Specifications 4,8.1.1.2.e.4 and 6. Failure of the CV-2 relay / telephone coil is revealed most easily and can be confirmed most often by visually checking the relays for visible targets. For this reason, and even though the CV-2 relay problem has been corrected, the CV-2 relays are included in the equipment walkdowns performed by plant operators during each shift. In fact, the failures leading to this request were identified during equipment walkdowns in spite of the fact that the diesel generator was being tested on a weekly frequency as a result of the June 7 failure.
IP believes that the corrective actions which have been taken (i.e., modification of the CV-2 relays) will prevent recurrence of relay failure due to excessive current. As noted above, correction of the overcurrent condition has been confirmed by measurement. It is therefore unnecessary and inappropriate to be testing the diesel generator at an increased frequency since such increased testing does not contribute to ensuring continued EDG reliability in response to these failures. Further, the results of numerous NRC and industry studies have identified that excessive or unnecessary testing of diesel generators can cause unnecessary wear or degradation and thus contribute to their reduced reliability. IP believes that increased testing of this diesel generator as a result of this event is unnecessary and could contribute to reduced reliability of the CPS onsite AC power source.
In addition to the above concerns, testing of the EDG(s) in accordance with the Technical Specifications requires the diesel generator (s) to be connected with offsite power and loaded to rated conditions. NRC Information Notice 84-69 warns against operating diesel generators connected to offsite power unnecessarily as disturbances in the offsite power system or in non-vital loads can adversely affect availability of the diesel generator.
Because these tests are being performed on an accelerated frequency, they result in an increased potential for reducing the availability of the diesel generator due to disturbances in the offsite power system or non-vital loads. Thus, the accelerated testing has the potential to result in a reduction in plant safety.
Safety Significance The compensatory actions taken in response to the identified failure of the CV-2 relay / telephone coil ensure the relays in both Division 1 and 2 will perform their function when required. The design change that has been implemented should prevent this failure from occurring again, and notwithstanding, the breakers will continue to be monitored to 1 confirm normal relay status. IP believes that these actions have corrected the condition and that these relays will not fail when required to perform their function during a LOOP.
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With respect to the safety significance of not continuing weekly testing of DG1 A, continued reliability is ensured by the actions that have been taken to address the relay l failure and not by increased testing of the diesel generator itself. Terminating increased testing may in fact have a positive safety benefit since, as discussed previously, increased testing can (1) cause unnecessary wear or degradation and thus reduce reliability of the diesel generator and (2) increase the potential for causing adverse effects on the diesel generator when connected to offsite power system.
Request Duration As described above, IP has been testing DGI A on a weekly schedule since the valid failure l occurred on June 7,1994. The most recent test failure which occurred on July 12,1994 I will result in the continuation of weekly testing until seven consecutive failure-free demands have been performed and the number of failures is less than or equal to one in the last 20 valid tests. Assuming there are no further failures, this will require at least 9 more weekly tests to be performed on DGI A before the normal, monthly test frequency can be resumed.
To supplement this request for enforcement discretion, IP is submitting a proposed change to the CPS Technical Specifications (see Attachment 3). The proposed change would revise Technical Specification Table 4.8.1.1.2-1 footnote "*" to exclude the August 3, 1993; June 7,1994; and July 12,1994 DGI A valid test failures from the total number of failures used to determine the diesel generator test frequency. In effect, this would return the test frequency for DGI A to monthly since there have been no other valid test failures of DGI A subsequent to August 3,1992. Enforcement discretion would be in effect until approval of the proposed change to the CPS Technical Specifications.
Basis for No Significant Hazards Consideration In view of the above, IP does not consider this request to be safety significant. According to 10CFR50.92, a proposed change to the license (Technical Specifications) involves no i significant hazards considerations if operation of the facility in accordance with the '
proposed change would not: (1) involve a significant increase in the probability or the consequences of any accident previously evaluated; or (2) create the possibility of a new or difTerent kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety. The proposed request for enforcement discretion is evaluated against each of these criteria below.
(1) As discussed previously, corrective actions have been taken to address the identified relay / telephone coil failure. These corrective actions will maintain or l restore the reliability of DGI A without increased testing as increased testing !
should not be necessary to confirm acceptable diesel generator performance or reliability in light of the corrective actions taken. The corrective actions taken and continued surveillance testing at the normal / routine test frequency provide
Attachment 2 to U-o02316 Page 6 of 6 l I assurance that DGI A will remain capable of performing its intended function of providing emergency standby power for systems designed to mitigate the consequences of certain accidents. This request therefore does not result in a significant increase in the probability or the consequences of any accident previously evaluated.
(2) This request does not result in a change to the plant design or operation as the scope of the potential impact of this request is limited to the test frequency for the diesel generator. As a result, no new failure modes are introduced and the request will therefore not create the possibility of a new or difTerent kind of accident from any accident previously evaluated.
(3) Other than the potential impact on the frequency of testing performed on the diesel generator, the proposed request involves no changes to the plant design or operation. In addition, as noted previously, this request would reduce the potential for unnecessary increased testing of the diesel generator which could adversely affect diesel generator reliability. As also noted previously, the corrective actions taken to address the identified relay failure provide assurance that diesel generator reliability can no longer be reduced due to premature CV-2 relay failure. The proposed request should not therefore have any significant adverse impact on the reliability or performance of the diesel generator and therefore does not constitute a significant reduction in a margin of safety with respect to these concerns.
Based on the foregoing, IP concludes that this request does not involve significant hazards considerations.
Environmental Considerations IP has reviewed this request against the criteria of 10CFR51.22 for categorical exclusion from environmental impact considerations. The request does not involve a significant hazards consideration, or significantly increase the amounts or change the types of efiluents that may be released offsite, nor does it significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, IP concludes that the proposed request meets the criteria given in 10CFR51.22(c)(9) for a categorical exclusion from the requirement for an Environmental Impact Statement and therefore does not involve irreversible environmental consequences.
Attachment 3 to U-602316 LS-94-012 Page1of5 EROPOSED CHANGE TO CPS TECHNICAL SPECIFICATIONS
Background
Clinton Power Station (CPS) Technical Specification (TS) 3/4.8.1.1, "AC Sources-Operating," specifies the operability requirements for AC sources at CPS during Operational Conditions 1,2, and 3 as well as those surveillance requirements which must be performed to demonstrate the operability of these AC sources. Specification 4.8.1.1.2 specifies the surveillances specifically required to demonstrate operability of the diesel generators. The surveillance requirements stated in 4.8.1.1.2.a are required to be performed on a STAGGERED TEST BASIS in accordance with the frequency specified on TS Table 4.8.1.1.2-1, " Diesel Generator Test Schedule." Surveillance Requirements 4.8.1.1.2.a.4 and 5 require the diesel generators to be started, verified to accelerate to the required speed and attain the required voltage and frequency within the required time (12 seconds), synchronized to offsite power, and run loaded for at least 60 minutes.
TS Table 4.8.1.1.2-1 requires a diesel generator to be tested on one of two test frequencies (monthly or weekly) based on the diesel generator's previous test performance history. Specifically, Table 4.8.1.1.2-1 requires a diesel generator to be tested at least once every 31 days if the number of valid failures in the last 20 valid tests is less than or equal to one and the number of valid failures in the last 100 valid tests is less than or equal to four. Table 4.8.1.1.2-1 also requires the diesel generator to be tested at least once per seven days if the number of valid failures in the last 20 valid tests is greater than or equal to two and/or the number of valid failures in the last 100 valid tests is greater than or equal to five. This weekly test frequency must be maintained until seven consecutive failure-free demands have been performed and the number of failures in the last 20 valid tests has been reduced to less than or equal to one.
The CPS Division i diesel generator (DGl A) is currently being tested on a weekly basis and has been tested at this frequency since an operator discovered the relay targets dropped on the DGI A A-B phase and B-C phase undervoltage relays on June 7,1994.
Although the emergency diesel generator (EDG) was in standby at the time the targets were observed, this event was considered a valid failure of the EDG because failure of either of these relays, which are part of the permissive-to-close circuitry for the DGI A output breaker, would allow premature closure of the breaker upon receipt of an automatic start signal due to or coincident with a loss ofoffsite power. As a result of the relay failure that occurred on July 12,1994, the current requirements of TS Table 4.8.1.1.2-1 require weekly testing of DGI A to be continued for 9 more weeks assuming -
there are no additional failures. (Afler 9 more weekly tests, the number of failures of DGl A in the last 20 valid tests will then be reduced to one, assuming no more failures.)
Because of the nature of the CV-2 failure and the corrective actions taken as a result, as well as the fact that the testing required by TS Table 4.8.1.1.2-1 does not confirm proper
Attachment 3 to U-602316 LS-94-012 Page 2 of 5 CV-2 relay, Illinois Power (IP) believes that continued weekly testing of DG1 A is unwarranted Therefore, in response to the current testing requirements imposed on DGl A, IP proposes to revise CPS TS Table 4.8.1.1.2-1 to exclude the DGI A CV-2 relay failures from the total number of failures used to determine the diesel generator test frequency.
Descrip_ tion of Proposed Channgc In accordance with 10CFR50.90, IP proposes to revise the first paragraph of footnote "*" ,
to CPS TS Table 4.8.1.1.2-1 to read as follows:
"* Criteria for determining number of failures and number of valid test shall be in accordance with Regulatory Position C.2.e of Regulatory Guide 1.108, but determined on a per diesel generator basis, except that the valid test failures of the Division 1 diesel generator identified on August 3,1993; June 7,1994: and July 12,1994 may be excluded from the total number of failures used to determine the diesel generator test frequency."
This proposed change is identified on the marked-up copy of the page from the current CPS TS contained in Attachment 4.
As the NRC staffis currently reviewing IP's request to adopt the Improved Technical Specifications (ITS) (reference IP letter U-602196 dated October 26,1993), the effect of the proposed change on IP's ITS submittal is reflected in a marked-up copy from the CPS ,
ITS submittal contained in Attachment 5.
Justification for Proposed Change As stated in the bases for CPS TS 3/4.8.1, the operability of the AC power sources and their associated distribution systems during plant operation ensures that suflicient power will be available to supply the safety related equipment required for (1) the safe shutdown of the facility and (2) the mitigaden and control of accident conditions within the facility.
In order to ensure the AC power supplies are available to meet these needs, the TS require an extensive series of surveillance tests. As noted above, TS Table 4.8.1.1.2-1 requires accelerated testing of the diesel generator based on the previous test performance history.
This requirement for increased testing is based upon maintaining a target reliability for each diesel generator unit and provides a timely response to the possibility of abrupt diesel /
generator degradation.
While increasing the testing frequency of an EDG is considered to be an acceptable method for demonstrating that the reliability of the EDG has been restored, it is also necessary to consider the impact ofincreased testing on the EDG. The results of e
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Attachment 3 to U-602316 LS-94-012 Page 3 of 5 numerous NRC and industry studies have indicated that excessive or unnecessary testing of diesel generators can cause unnecessary wear or degradation and thus contribute to their reduced reliability. In addition, testing of the EDGs in accordance with the Technical Specifications requires the diesel generators to be operated and connected with offsite power and loaded to rated conditions. NRC Information Notice 84-69 warns against operating diesel generators connected to offsite power unnecessarily as disturbances in the offsite power system or in non-vital loads can adversely afTect availability of the diesel generator. Because these tests are being performed on an accelerated frequency, they result in an increased potential for reducing the availability of the diesel generator due to disturbances in the offsite power system or non-vitalloads. Thus, increased testing has the potential to contribute to reduced reliability of the CPS onsite AC power source as well as the potential to also result in a reduction in plant safety.
This proposed change simply excludes the three recent DGl A CV-2 relay failures (i.e.,
August 3,1993; June 7,1994; and July 12,1994) from the total number of failures used to determine the diesel generator test frequency. As noted above, the testing required by CPS TS Table 4.8.1.1.2-1 does not confirm proper operation of the CV-2 relay.
Therefore accelerated testing of DGl A in accordance with TS Table 4.8.1.1.2-1 does not provide assurance of diesel generator reliability for these failures. IP has taken i appropriate corrective action in response to the three failures referenced above.
Acceptable reliability of the Division I diesel generator is thus assured without increased testing in response to those failures.
This change will not affect the requirement to perform accelerated testing on DGI A for any other future valid test failures (providing the criteria for required weekly testing are met). Reliability of the EDGs will thus continue to be confirmed by testing required in accordance with the Technical Specifications.
Easis For No Significant Hazards Consisleration In accordance with 10CFR50.92, a proposed change to the operating license (Technical Specifications) involves no significant hazards consideration if operation of the facility in accordance with the proposed change would not: (1) involve a significant increase in the probability or consequences of any accident previously evaluated, (2) create the possibility of a new or difTerent kind of accident from any accident previously evaluated, or (3) involve a significant reduction in a margin of safety. The proposed changes are evaluated against each of these criteria below.
1 Attachment 3 to U-602316 LS-94-012 Page 4 of 5 (1) The proposed change itself does not involve any changes to the plant design or operation and therefore does not affect any initiators of any previously evaluated accidents. Consequently the proposed change does not involve any significant increase in the probability of occurrence of any accident previously evaluated.
The proposed change only allows certain identified test failures of the Division 1 diesel generator to not be included in the total number of failures used to determine whether testing of the diesel generator should be increased. Because appropriate corrective action has been taken in response to those particular test failures, acceptable reliability of the Division 1 diesel generator is assured without increased testing in response to those failures. Further, the CPS design includes redundancy and consideration of single-failure criteria such that alternate sources, both onsite and offsite, are provided to ensure safe shutdown of the facility in the event of an accident, including mitigation of the consequences of an accident.
Based on the above, IP concludes that the proposed change will not increase the consequences of any accident previously evaluated.
(2) The proposed change does not involve any modification to plant design or operation which could introduce a new failure mode. The proposed change only impacts the frequency of testing of the Division I diesel generator as it does not directly afTect operation or the design of the Division 1 diesel generator or any other plant stmeture, system or component. As a result, no new failure modes are introduced and the proposed change will therefore not create the possibility of a new or difTerent kind of accident from any accident previously evaluated.
(3) As noted above, other than the impact on the frequency of testing performed on the Division I diesel generator, the proposed change involves no changes to the plant design or operation. Therefore, as they are typically defined or established by thc plant's accident analyses, no margins of safety are impacted by the proposed change. Notwithstanding, if diesel generator reliability is viewed as a margin of safety, Division 1 diesel generator reliability is the only margin of safety potentially impacted by the proposed change. However, as noted previously, reliability of the Division 1 diesel generator is not adversely affected by the proposed change since the corrective actions taken in response to the noted failures provide assurance of acceptable diesel generator reliability without increased testing in response to these failures. Further, the proposed change will reduce the potential for excessive or unnecessary increased testing of the diesel generators which may adversely affect diesel generator reliability through wear and degradation. Precluding unnecessary testing of the diesel generators will also limit the potential reduction in plant safety l resulting from disturbances in the offsite power system or in non-vital loads. In total, the proposed change does not therefore involve a significant reduction in a margin of safety. l
. Attachment 3 to U-602316 LS-94-012 Page 5 of 5 Based on the foregoing, IP concludes that this proposed change does not involve a significant hazards consideration.
Ertvi_ronmental Considsr_ati_gns n IP has reviewed the proposed change against the criteria of 10CFR51.22 for categorical exclusion from environmentalimpact considerations. The proposed change does not involve a significant hazards consideration, or significantly increase the amounts or change the types of effluents that may be released offsite, nor does it significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, IP concludes that the proposed change meets the criteria given in 10CFR51.22(c)(9) for a categorical exclusion from the requirement for an Environmental Impact Statement.
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. Attachment 4 to U-602316 LS-94-012 Page1of2 l
Proposed Changes to the Current Technical Specifications
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