ML20064C153

Application for Amends to Licenses NPF-4 & NPF-7,eliminating Unnecessary EDG Surveillance Requirements in Accordance W/Gl 93-05 & NUREG-1366

ML20064C153
Person / Time
Site:	North Anna
Issue date:	03/01/1994
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20064C154	List: ML20064C153 ML20064C156
References
RTR-NUREG-1366 94-120, GL-93-05, GL-93-5, NUDOCS 9403090165
Download: ML20064C153 (9)

Text

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VInmNIA ELECTHIC AND POWER COMi%NY Incunown,VinmNIA 20261 March 1, 1994 U.S. Nuclear Regulatory Commission Serial No.94-120 4

Attention: Document Control Desk NL&P/EJW Washington, DC. 20555 Docket Nos. 50-338 50-339 License Nos. NPF-4 ,

NPF-7 l Gentlemen: 1 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 PROPOSED TECHNICAL SPECIFICATIONS CHANGES -;

REMOVAL OF UNNECESSARY EMERGENCY DIESEL GENERATOR 1 SURVEILLANCE REQUIREMENTS IN ACCORDANCE WITH l

NRC GENERIC LETTER 93-05 Pursuant to 10 CFR 50.90, the Virginia Electric and Power Company requests amendments, in the form of changes to the Technical Specifications, to Facility Operating License Nos. NPF-4 and NPF-7 for North Anna Power Station Units 1 and 2, respectively. The proposed changes will eliminate certain surveillance requirements for the emergency diesel generators which have been deemed unnecessary. These changes are in accordance with the NRC Technical Specification improvement Program as documented in Generic Letter 93-05, "Line-Item Technical Specifications Improvements For Testing During Power Operation," and NUREG-1366,

" improvements To Technical Specifications Surveillance Requirements."

A discussion of the proposed Technical Specifications changes is provided in Attachment 1. The proposed Technical Specifications changes are provided in Attachment 2. It has been determined that the proposed Technical Specifications changes do not involve an unreviewed safety question as defined in 10 CFR 50.59 or i a significant hazards consideration as defined in 10 CFR 50.92. The basis for our determination that these changes do not involve a significant hazards consideration is provided in Attachment 3. The proposed Technical Specifications changes have been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Management Safety Review Committee.

Should you have any questions or require additional information, please contact us.

Very truly yours,

)LSM W. L. Stewart Senior Vice President - Nuclear i

i 9403090165 940301 ib PDR ADOCK 05o00338 {

P PDR .

4 Attachments cc: U.S. Nuclear Regulatory Commission Region ll 101 Marietta Street, N.W.

Suite 2900 Atlanta, Georgia 30323 Mr. R. D. McWhorter NRC Senior Resident inspector Nodh Anna Power Station Commissioner Depadment of Health Room 400 109 Governor Street Richmond, Virginia 23219

COMMONWEALTH OF VIRGINIA )

)

COUNTY OF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by W. L. Stewart who is Senior Vice President -

Nuclear, of Virginia Electric and Power Company. He is duly authorized to execute and file the foregoing document in behalf of that Company, and the statements in the document are true to the best of his knowledge and belie .

Acknowledged before me this day of(

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My Commission Expires: L //M . f/ .19 #d

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a Notary Public i

(SEAL)

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Attachment 1 Discussion of Changes i

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Discussion of Chanaea introduction The NRC has completed a comprehensive examination of surveillance requirements in technical specifications that require testing at power. The evaluation is documented in NUREG-1366, " improvements to Technical Specification Surveillance Requirements," dated December 1992. The NRC staff found, that while the majority of testing at power is important, safety can be improved, equipment degradation decreased, and an unnecessary burden on personnel resources eliminated by reducing the amount of testing at power that is required by technical specifications.

Based on the results of the evaluations documented in NUREG-1366, the NRC issued Generic Letter 93-05, "Line-Item Technical Specifications improvements to Reduce Surveillance Requirements for Testing During Power Operation," dated September 27, 1993.

The safety function of the emergency diesel generators (EDG's) is to supply AC electrical power to plant safety systems whenever the preferred AC power supply is unavailable. Consistent with Generic Letter 93-05, item 10.1 and NUREG-1366, we are requesting a change to the testing requirements of an operable EDG when the other EDG is inoperable or an offsite circuit is inoperable, the separation of the hot restart test of an EDG from the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> loaded run, and the elimination of fast loading of EDG's except for the 18 month surveillance test of the Loss of Offsite Power (LOOP) capability.

Backaround North Anna Power Station is a dual unit site with four emergency diesel generators.

Two emergency diesel generators are dedicated for each unit. North Anna Technical Specification 3/4.8.1.1 requires that while in Modes 1 through 4, as a minimum, each unit will have two physically independent circuits between the offsite transmission network and the onsite Class 1E distribution system, and two separate and independent diesel generators.

The current North Anna Technical Specification 3/4.8.1.1 requires that operable EDG's be started and loaded to demonstrate their operability in the event an offsite AC source (s) becomes inoperable. The intent of this testing is to provide added assurance that the operable EDG's are capable of supplying emergency power when the offsite AC sources are degraded (e.g., power fluctuations in the grid, loss of one or both offsite AC power sources). The most probable cause of an offsite AC source becoming degraded is severe weather or an off-normal grid condition. Feedback from sevote weather or other off-normal grid conditions can also cause the loss of an EDG (if the EDG is tied to the offsite source when it becomes inoperable) leaving the EDG's safety bus without an AC power source. NRC Information Notice 84-69 warns that disturbances on the offsite source can adversely affect EDG reliability when an EDG is operated connected to offsite sources. Therefore, EDG availability is potentially lessened by requiring a demonstration of operability which connects the EDG to the

1 same grid being supplied by offsite AC power. Since the surveillance testing schedule established in Regulatory Guide 1.9 (Revision 2, December 1979) provides adequate assurance that the operable EDGs will be capable of performing their intended safety functions, deletion of the Technical Specification requirement to start and load operable EDG's when an offsite AC source becomes inoperable does not increase the probability that the operable EDG's will be unable to perform their safety function.

Therefore, in accordance with NRC Generic Letter 93-05, we are requesting that North Anna Technical Specifications be amended to delete the requirement to conduct operability testing of the EDG's when one or both offsite AC sources become inoperable.

Operability testing of an EDG is also required by North Anna Technical Specification 3/4.8.1.1 whenever the alternate safety buses' EDG is declared inoperable due to any cause other inan preplanned preventative maintenance or testing. Since there are many potential failures of EDG subsystems that would not be classified as a common

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mode failure yet would cause an EDG to be declared inoperable, this Technical Specification requirement can cause unnecessary testing of the operable EDG when the alternate safety buses' EDG is declared inoperable due to inoperable support equipment or an independently testable component. NUREG-1366 stated that "The NRC staff recommends that the requirements to test the remaining diesel generator (s) when one diesel generator is inoperable due to any cause other than preplanned preventative maintenance or testing be limited to those situations where the cause for inoperability has not been conclusively demonstrated to preclude the potential for a common mode failure. However, when such testing is required, it should be performed within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of having determined that the diesel generator is inoperable." In accordance with NRC Generic Letter 93-05, we are requesting that North Anna Technical Specifications be amended to incorporate the recommendations of NUREG-1366 by requiring operability testing of an EDG only when the alternate safety buses' EDG is declared inoperable for any cause other than an inoperable support system, an independently testable component, or preplanned preventative maintenance or testing. This testing shall be completed within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, unless the absence of any potential common mode failure for the remaining diesel generator is conclusively demonstrated.

North Anna Technical Specification 3/4.8.1.1 currently requires that during the EDG fast start surveillance test conducted at least once per 184 days, the EDG be loaded to an indicated 2500 to 2600 kW in less than or equal to 60 seconds. As stated in NUREG-1366, this fast loading is the most significant cause of accelerated degradation of diesel generators. In accordance with NRC Generic Letter 93-05, we are requesting that North Anna Technical Specifications be amended to delete the fast loading requirements and allow gradual loading in accordance with the manufacturer's recommendations for all surveillance requirements with the exception of the once per refueling outage Loss of Offsite Power surveillance test which will still require full loading in less than or equal to 60 seconds.

North Anna Technical Specification 3/4.8.1.1 currently requires that within 5 minutes of shutting down the EDG following the once per refueling outage 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> loaded test l run that the Loss of Offsite Power (LOOP) surveillance test be conducted. The sequencing of the LOOP test following the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> loaded test run can have a l

I significant impact on the outage schedule. Unnecessary outage delays could result from the inability to conduct the LOOP test within the 5 minute time constraint following the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> run. Additionally NUREG 1366 stated that "There is no safety reason for performing a startup of a diesel within 5 minutes of the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test run as is required by Technical Specifications." As described in NUREG-1366, on February 15,1988, Duke Power Company proposed to separate the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test run from the 5 minute hot restart test. The reason for requesting this change was that separating these two required tests gave the plant operators added flexibility and prevented critical path complications during the outages. This change was approved by the NRC on July 28, 1988. Virginia Electric and Power Company requests the same change for North Anna by eliminating the requirement for the LOOP test following the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> loaded run and adding a new surveillance requirement of a simple hot restart test following a 2 hourloaded run of the EDG.

Additional minor administrative changes are included in this amendment request to correct typographical errors and improve readability.

Specific Chanaes These Technical Specification (TS) changes apply to both Unit 1 and Unit 2 (unless otherwise noted).

i TS 3.8.1.1 Actions are being changed as follows :

Action "a" Delete sentence "If either EDG has not been successfully tested within the past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, demonstrate its OPERABILITY by performing Surveillance Requirement j 4.8.1.1.2.a.4 separately for each such EDG within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." i Action "b" . End the first sentence at "thereafter" by deleting the semi-colon (;) and adding a period (.). Delete the remainder of Action "b" and replace with "If the EDG became inoperable due to any cause other than an inoperable support system, an independently testable component, or preplanned preventative maintenance or testing, demonstrate the OPERABILITY of the remaining OPERABLE EDG by performing Surveillance Requirement 4.8.1.1.2.a.4 within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> *, unless the absence of any potential common mode failure for the remaining diesel generator is dernondrated. Restore the diesel generator to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be at 19ast HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

At the bottom of page 3/4 8-1 replace the single asterisk (*) item with "'This action is required to be completed regardless of when the inoperable EDG is restored to OPERABILITY."

Action "c" : In the first sentence after " .. and if the EDG became inoperable due to any cause other than" add "an inoperable support system, an independently testable component, or." In the first sentence after "... within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> *" delete semicolon (;) and insert ", unless the absence of any potential common mode failure for the remaining diesel generator is demonstrated," and end the sentence. Start a new sentence at

" Restore one of the inoperable ..." Delete the last sentence of Action "c" since a diesel test may not be required.

Action "d" : In the first sentence delete the phrase "; demonstrate the OPERABILITY of two diesel generators by sequentially performing Surveillance Requirement 4.8.1.1.2.a.4 on both diesels within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> unless the diesel generators are already operating;." in the first sentence after " HOT STANDBY" delete the misspelled word "wtihin" and replace with "within" (misspelled on Unit 1 only). In the second sentence after "Following restoration of one offsite" delete the misspelled word "cource" and replace with " source" (misspelled on Unit 1 only). Delete the last sentence of Action 4

"d" as diesel testing is not required.

i Action "e" - The last sentence of this action is deleted since it is unnecessary clarification.

At the bottom of page 3/4 8-2 replace the single asterisk (*) item with "*This action is required to be completed regardless of when the inoperable EDG is restored to OPERABILITY."

SR 4.8.1.1.2.c : Change the third sentence to read "The generator shall be manually i synchronized to its appropriate emergency bus, gradually loaded " to an indicated 2500 to 2600 kw*", and operated for at least 60 minutes."

SR 4.8.1.1.2.d.7 : Delete the last sentence.

SR 4.8.1.1.2.d.9.a) (Unit 1 only) : Replace the period (.) with a comma (,).

SR 4.8.1.1.2.d.10 (Unit 1 only) : Delete the second "a)" and insert "b)."

SR 4.8.1.1.2.d : Add surveillance requirement after SR 4.8.1.1.2.d.10:

"11. Verifying the diesel generator's hot restart capability by:

a) Operating the diesel generator" loaded to an indicated 2500 to 2600kW"* for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or until operating temperatures have stabilized, and b) Within 5 minutes of shutdown verify the diesel generator can be started" and accelerated to at least 900 rpm in less than or equal to 10 seconds. The generator voltage and

frequency shall be 4160 i 420 volts and 60 i 1.2 Hz within 10 seconds after the start signal."

Page 3/4 8-6 (Unit 2 only) : Add notation "" This test band is meant for i guidance to avoid routine overloading of the engine. Loads in excess of this band for special testing under direct monitoring of the manufacturer or momentary variations due to changing bus loads shall not invalidate the test."

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l Safety Slanificance i

The proposed changes to the operability testing and surveillance requirements for the Emergency Diesel Generators (EDGs) are consistent with the intent of Generic Letter 93-05, "Line-Item Technical Specifications improvement to Reduce Surveillance Requirements for Testing During Power Operation," dated September 27,1993. The proposed changes will modify the requiremont for operability testing of an EDG when the alternate safety buses' EDG is inoperable, delete the requirement for operability testing of the EDG's when one or both offsite AC sources are inoperable, eliminate fast loading of EDG's except for the LOOP test, and separate the hot restart test from the 24 ,

hourloaded test run of the EDG's. j Changing the operability testing requirements and surveillance requirements of the ,

EDG docc not affect the probability of occurrence or the consequences of the l accidents identified in the UFSAR. No new accident precursors are being generated  !

by the proposed surveillance requirement. Furthermore, the EDGs will continue to be tested in accordance with Revision 2 of Regulatory Guide 1.9 (December 1979) which provides assurance that the system is capable of performing its intended safety function. Therefore, the consequences of a postulated accident are not increased by ,

these changes in operability testing or surveillance requirements for the EDGs.

The reduced operability testing and modified surveillance requirements of the EDGs will not significantly increase the probability of a malfunction of an EDG to perform its intended safety function. This reduction in operability testing and modified surveillance requirements of the EDGs at power has been examined and accepted by the NRC staff in Generic Letter 93-05, item 10.1. The staff found that while the majority of the testing at power is important, safety can be improved, equipment degradation decreased, and an unnecessary burden on personnel resources eliminated by l reducing the amount of testing at power that is required by Technical Specifications.

This change in the operability testing and surveillance requirements does not affect plant or EDG operations. Therefore, no new accident precursors are being generated by these proposed changes for the EDGs.

Operability testing and surveillance testing of the EDGs will continue to be performed in accordance with Revision 2 of Regulatory Guide 1.9 (December 1979). These changes will improve the overall reliability of the EDGs by reducing unnecessary  ;

starting and loading thereby reducing the wear and tear on those machines.

Therefore, these changes in operability testing and surveillance testing requirements 4

for the EDGs do not reduce the margin of safety as described in the Technical Specifications.

d