ML12279A208

TSTF-531 RAIs

ML12279A208
Person / Time
Site:	Technical Specifications Task Force
Issue date:	10/19/2012
From:	Michelle Honcharik Licensing Processes Branch (DPR)
To:	Technical Specifications Task Force
Honcharik M
References
TAC ME8309, TAC ME8310
Download: ML12279A208 (11)

Text

October 19, 2012 Technical Specifications Task Force (TSTF) 11921 Rockville Pike, Suite 100 Rockville, MD 20852

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION RE: TRAVELER TSTF-531, REVISION 0, REVISION OF SPECIFICATION 3.8.1, REQUIRED ACTION B.3.1 AND B.3.2 (TAC NOS. ME8309 AND ME8310)

Dear Members of the TSTF:

By letter dated March 29, 2012 (Agencywide Documents Access and Management System Accession No. ML12089A317), the TSTF submitted for U.S. Nuclear Regulatory Commission (NRC) staff review Traveler TSTF-531, Revision 0, Revision of Specification 3.8.1, Required Action B.3.1 and B.3.2. Upon review of the information provided, the NRC staff has determined that additional information is needed to complete the review. On October 5, 2012, Brian Mann, Vice President of Industry Programs, EXCEL Services Corporation, and I agreed that the NRC staff will receive your response to the enclosed request for additional information (RAI) questions within 90 days of the date of this letter. If you have any questions regarding the enclosed RAI questions, please contact me at 301-415-1774 or Michelle.Honcharik@nrc.gov.

Sincerely,

/RA/

Michelle C. Honcharik, Sr. Project Manager Licensing Processes Branch Division of Policy and Rulemaking Office of Nuclear Reactor Regulation Project No. 753

Enclosure:

As stated cc w/encl: See next page

ML12279A208; *via memo (ML12264A533) NRR-106 OFFICE PLPB/PM PLPB/LA STSB/ABC PLPB/BC (A) PLPB/PM NAME MHoncharik DBaxley MHamm* SStuchell MHoncharik DATE 10/5/2012 10/16/2012 9/17/2012 10/18/2012 10/19/2012 REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION TRAVELER TSTF-531, REVISION 0, REVISION OF SPECIFICATION 3.8.1, REQUIRED ACTION B.3.1 AND B.3.2 TECHNICAL SPECTIFICATIONS TASK FORCE (TSTF)

PROJECT NO. 753 The Traveler TSTF-531, Revision 0, proposes to revise the Standard Technical Specification (STS) Condition B of Specification 3.8.1, AC Sources - Operating, to clarify the requirements for performance of a common cause failure (CCF) determination for an inoperable diesel generator (DG).

Item 1 The traveler proposes to add a Note to Required Action B.3 which states:

Required Actions B.3.1 and B.3.2 are not required to be performed if the DG is inoperable due to preplanned maintenance or testing, or an inoperable support system.

STS 1.1, Definition of OPERABLE - OPERABILITY, states:

A system, subsystem, train, component, or device shall be OPERABLE or have OPERABILITY when it is capable of performing its specified safety function(s) and when all necessary attendant instrumentation, controls, normal or emergency electrical power, cooling and seal water, lubrication, and other auxiliary equipment that are required for the system, subsystem, train, component, or device to perform its specified safety function(s) are also capable of performing their related support function(s).

Question 1a Given the above STS 1.1 definition of OPERABILITY, explain how the proposed traveler addition of Technical Specification (TS) Note will continue to ensure the Operability of the redundant DG and that no CCF exists in the redundant DG.

Question 1b Please refer to Regulatory Guide 1.9, Revision 3 or 4, Figure 1, Boundary and Support Systems of Emergency Diesel Generator Systems. Identify the specific DG support systems, required for the DG to perform its specified safety function(s), that are included in the proposed Note or an inoperable support system [an exception to perform the TS 3.8.1 Condition B, Required Action B.3.1 or B.3.2].

ENCLOSURE

NRC Information Notice 2007-27, Recurring Events Involving Diesel Generator Operability, states:

One recurrent event that continues to stand out involves the vibration-induced failure of EDG [emergency DG] piping and tubing. In many cases, major piping failures occurred after minor leaks were identified and not immediately or properly repaired by the licensee.

Some licensees have put off repairing minor leaks until the next scheduled EDG outage. If this is the case and TSTF-531 is approved, Required Action B.3.1 would not be performed on the redundant EDG because the minor leak would be repaired during a scheduled EDG outage.

The redundant EDG would not have to be inspected to ensure it does not have a similar leak/piping or tubing degradation.

Question 1c Explain how a similar leak on a redundant EDG would be identified and repaired prior to that EDGs next operation or maintenance outage.

NRC Staff Comment 1 Suggested Condition B, Required Action B.3.1/B.3.2 Note:

Note 1: B.3.1 and B.3.2 are not required to be performed if the DG is inoperable solely for preplanned maintenance or testing.

DG failures or failure mechanisms identified during preplanned maintenance or testing are not included in this exception.

Item 2 The marked-up TS Bases B.3.1 and B.3.2 state:

If the DG is inoperable due to a DG component that can be tested without starting the OPERABLE DG (e.g., [cooling water, ventilation equipment, starting air pressure, diesel fuel oil or diesel lubricating oil volume or quality]), testing of the component on the OPERABLE DG may be sufficient to determine the redundant DG is not inoperable due to common cause failure, thereby meeting B.3.1.

Question 2a Identify all DG components that can be tested without starting the Operable DG per the specific engine manufacturer (i.e., Fairbanks Morse, ALCO, EMD, SACM, etc.).

Question 2b From the list of components identified in your response to Question 2a above, identify those components that can be tested without requiring the Operable DG being in an inoperable condition for testing.

Question 2c STS 3.8.3 limiting condition for operation (LCO) Required Actions apply directly to the DG starting air, fuel oil and lube oil system volume, and fuel oil quality. The Required Actions do not require the DG to be tested or a CCF determination to be performed upon entry into the TS Actions. Explain why these systems are included in the proposed marked-up TS Bases B.3.1 and B.3.2.

The Traveler states:

performing tests on independently testable components would actually be part of a common cause failure determination, which is already required to be done. Performance of such tests is not a true exception to the requirement to perform a common cause failure determination, so it is addressed by including a sentence within the Bases.

Question 2d If performing tests on the Operable DG independently testable components would be part of the CCF determination and required to be performed, as stated above, why is the exception to performance of B.3.1 proposed in the Note, and in the TS Bases B.3.1 and B.3.2?

Question 2e Indentify all DG components that are independently testable per the specific engine manufacturer (i.e., Fairbanks Morse, ALCO, EMD, SACM, etc.).

Question 2f Given the STS 1.1 definition of Operability, explain how the proposed TS Bases exception ensures that a failure of an independently testable component does not affect the OPERABILITY of the opposite train DG if Required Action B.3.1 or B.3.2 is NOT performed.

The traveler TSTF-531 on Page 6 states that the proposed changes would result in a small decrease in the number of times that licensees perform B.3.1 or B.3.2. Also, on Page 7, the traveler TSTF-531 states that a survey of licensees identified that plants enter Condition B an average of 27 times per year per unit. Based on this data, it is estimated that Condition B would have been entered approximately 14,000 times over the 5 year period examined above without a single instance of a CCF. The NRC staff understands that the proposed exemptions to TS B.3.1 and B.3.2 include: (1) pre-planned maintenance and testing, (2) components that can be tested without starting the DG, (3) independently testable components, and (4) inoperable support systems governed by its own LCO.

Question 3a Please quantify the term small decrease as used above.

Question 3b If these exemptions are only expected to result in a small decrease in the estimated 14,000 entries into B.3.1 and B.3.2 as stated above, what specifically are the expected causes for the remaining large majority of entries into B.3.1 and B.3.2?

Question 3c Of the approximately 14,000 entries into TS 3.8.1, Condition B, how many diesel starts were performed versus common-cause determinations?

Question 3d If the proposed changes to B.3.1 and B.3.2 are only expected to result in a small decrease in the number of B.3.1 and B.3.2 entries, why is the change necessary?

Item 4 On Page 4 the Traveler states that licensees have continued to improve the quality and depth of their CCF determinations and licensee procedural requirements make it difficult to perform, review, and approve an adequate CCF determination in less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The starting [slow start with TS allowed engine pre-lube] of the redundant Operable DG reduces reliability and causes additional wear and tear.

Question 4a Please provide engine/generator manufacturer data to support this statement including the quantitative impact on DG reliability and DG wear and tear (i.e., reliability and longevity of the DG).

Question 4b Provide specific plant data for the past 7 years for licensees who have performed a TS required plant shutdown (10 CFR 50.72(b)(2)(i)) due to: (1) the inability to perform B.3.1 or B.3.2 within the required [24] hours, (2) because a new or different CCF mechanism was discovered after the [24] hour Completion Time (CT) had expired, or (3) because the initial CCF determination was discovered to be incorrect.

Question 4c The STS allow a licensee to perform the CCF determination as an alternative to starting the EDG. Licensees who choose to perform the CCF determination and later find that the CCF determination will take longer than anticipated, can, as an alternative, start the DG (perform a DG slow-start per surveillance requirement (SR) 3.8.1.2) prior to the expiration of the 24-hour CT to satisfy the TS Required Action. Explain why this option is causing a burden on licensees in order to demonstrate, in a timely manner, that a CCF mechanism does not exist on the Operable DG.

Question 4d Identify the specific procedural impediments to the timely performance, review, and approval of CCF determinations and explain why these impediments cannot be directly addressed by individual licensees. Provide specific (actual) examples where the procedural requirements prevented the CCF determination from being completed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and the resultant action(s) taken.

Question 4e For the past 7 years, please identify all licensees who have performed multiple (more than one)

CCF evaluations or re-performed the surveillance requirement (SR) test during the STS 72-hour DG CT period.

Item 5 On Page 6 the Traveler states:

A review of Licensee Event Reports (LERs) from 2005 thru August 2010 was performed to identify common cause failures of two or more trains of DGs. This resulted in the identification of 31 LERs that documented the simultaneous inoperability of two or more DGs. Each LER was then reviewed to determine if the simultaneous inoperability of the DGs was due to a common cause failure and, if so, if the common cause failure was identified by performance of Required Action B.3.1 (common cause failure determination) or Required Action B.3.2 (slow start of the Operable DG). There are no instances in which the other DG was found to be inoperable due to a common cause failure. There was only one instance in which the redundant DG was found to be inoperable by Required Action B.3.2 (Slow Start Test). In this instance, there was no common cause failure.

An NRC staff review of licensee 10 CFR 50.72(b)(2)(i) (shutdown required by TS) event notifications (ENs) made to the NRC Operations Center for plant shutdowns due to DG inoperability for the period March 2005 through August 2012 conflicts with the above statement.

Of the 29 total ENs, 14 ENs identified multiple (2 or more) DG inoperable, requiring a plant shutdown. Of those 14 ENs, one licensee identified that all (4) DGs were inoperable through performance of the CCF determination (EN#41895, Brunswick). Two other licensees identified the redundant DG to be inoperable during the performance of the surveillance test (EN#42820, Seabrook and EN#48186, Prairie Island). Additionally, the redundant DG was found to be inoperable at one other licensee facility due to an unrelated failure mechanism (not CCF) during the performance of the surveillance test (EN#45564, SONGS).

Question 5a Explain how the prohibited and unsafe operating conditions (i.e., loss of emergency power safety function - EN #42820, EN #48186, EN #41895, and EN#45564) would otherwise be identified in a timely manner if B.3.2 had not been not performed as required by TS.

On Page 5, the Traveler proposes that if a CCF mechanism is identified after the initial entry into Condition B and Required Action B.3.2 is performed (SR is performed), no action is required because those starts suffice to provide assurance of continued OPERABILITY of those DG(s).

Question 5b Explain and provide specific examples (include examples of human error discoveries, e.g.,

improper maintenance) and how the above proposed exception to perform either B.3.1 or B.3.2 (if Required Action B.3.2 was performed on initial entry into Condition B), provides continued assurance that the Operable DG is not affected by any new or different CCF mechanism and remains Operable in all cases.

Staff Comment 2 Consider the following Condition B, Required Action B.3.1/B.3.2 Note:

Note 2: Separate one-time performance of the Required Action NOT performed for the initial entry into Condition B is required if a new or different common cause failure mechanism is identified subsequent to initial entry into Condition B.

Item 6 The proposed Bases for the Required Action B.3.1 CT states:

Should a new or different potential common cause failure mechanism be discovered, the licensee is provided an additional 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to perform a revised common cause failure determination.

The Traveler states:

As evidenced by the NRC proposed Actions in GL 84-15, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> was considered to be a reasonable amount of time to confirm that the Operable DG was not affected by the same problem as the inoperable DG.

Question 6a As proposed, the Traveler could allow unlimited revisions to the original CCF determination without performance of B.3.1 or B.3.2 by resetting the original 24-hour CT before the initial CT has expired. TS LCO 3.8.1, Condition B (One [required DG] inoperable, has a 72-hour CT).

Explain how the proposed allowance to perform multiple revisions (24-hour CT resets) without performance of B.3.1 or B.3.2 would provide assurance of continued OPERABILITY of the Operable DG(s) during the 72-hour CT period.

Question 6b Explain why the proposed CCF determination would not be required to be completed within the LCOs Required Action Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (i.e., within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of declaring the DG inoperable). As proposed, it could be interpreted that the 24-hour CT would start from the time

after reaching a conclusion that the failure mechanism of the first inoperable DG is due to a CCF mechanism (i.e., the failure mechanism is first evaluated for potential for a common cause) and if determined to be a CCF mechanism, then the 24-hour CT would start to determine if the other Operable DG(s) is affected and is Operable.

Item 7 On Page 5, the Traveler states:

The other exception being added is when an inoperable support system governed by its own Technical Specification renders a supported DG inoperable. (Note: if the support system was not governed by its own LCO it would be not functional instead of inoperable, as Operability only applies to Technical Specification systems.) Under the ISTS usage rules, inoperability of a Technical Specification supported system would usually be addressed in the actions of the inoperable support system through application of LCO 3.0.6. In those cases, the Required Action to perform a common cause failure determination would not apply.

However, in some cases the support system LCOs (such as cooling water) direct that the Conditions and Required Actions of LCO 3.8.1 be followed. In these cases the cause of the inoperability is known (the inoperable support system) and the Conditions and Required Actions of the inoperable support system contain the appropriate compensatory measures. This exception for inoperable support systems was accepted by the NRC in the past as detailed in Section 3.2 Development of the Existing Requirements.

As stated above, STS 3.7.8, Service Water System (SWS), contains a Note (1) which states:

Enter applicable Conditions and Required Actions of LCO 3.8.1, AC Sources - Operating, for emergency diesel generator made inoperable by SWS.

Additionally, STS SR 3.7.8.1, is also modified by a Note which states:

Isolation of SWS flow to individual components does not render the SWS inoperable.

Question 7a Identify all DG support components, which have their own (system) TS LCO that cannot be exited once the DG support component is isolated/deenergized or would result in the support system being TS inoperable.

Question 7b Explain why a support system having its own LCO provides assurance that a CCF mechanism does not affect Operability of the Operable DG(s) in all situations.

Question 7c Identify all DG systems for which this proposed exception would apply and the specific actions in the system LCO that provide assurance of continued Operability of the Operable DG(s) in situations where the LCO does not specifically require the DG to be declared inoperable.

Technical Specifications Task Force Project No. 753 cc:

Technical Specifications Task Force 11921 Rockville Pike Suite 100 Rockville, MD 20852 Attention: Donald R. Hoffman E-mail: donaldh@excelservices.com Robert A. Slough Comanche Peak Nuclear Power Plant P. O. Box 1002, Mail Code A08 Glen Rose, Texas 76043 E-mail: robert.slough@luminant.com Roy A. (Tony) Browning Duane Arnold Energy Center 3277 DAEC Rd.

PSC/Licensing Palo, IA 52324-9785 E-mail: Tony.Browning@nexteraenergy.com Wendy E. Croft Exelon Nuclear 200 Exelon Way, Suite 340 Kennett Square, PA 19348 E-mail: Wendi.Croft@exeloncorp.com Otto W. Gustafson Entergy Nuclear Operations, Inc.

Palisades Nuclear Power Plant 27780 Blue Star Memorial Highway Covert, MI 49043 E-mail: ogustaf@entergy.com Brian D. Mann EXCEL Services Corporation 11921 Rockville Pike, Suite 100 Rockville, MD 20852 E-mail: brianm@excelservices.com