TSTF-17-01, TSTF Draft Response to NRC Questions on TSTF-505, Provide Risk-Informed Extended Completion Times for 02/16/2017 Public Meeting

TSTF Draft Response to NRC Questions on TSTF-505, Provide Risk-Informed Extended Completion Times for 02/16/2017 Public Meeting

ML17037C193
Person / Time
Site:	Technical Specifications Task Force
Issue date:	01/31/2017
From:	Gustafson O, Leisure M, Morris J, Redd J, Linda Williams Technical Specifications Task Force
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Honcharik M
Shared Package
ML17037C191	List: TSTF-17-01, TSTF Draft Response to NRC Questions on TSTF-505, Provide Risk-Informed Extended Completion Times for 02/16/2017 Public Meeting
References
TSTF-17-01
Download: ML17037C193 (16)

Text

TECHNICAL SPECIFICATIONS TASK FORCE DRAFT TSTF A JOINT OWNERS GROUP ACTIVITY DATE TSTF-17-01 PROJ0753 Attn: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Response to NRC Questions on TSTF-505, "Provide Risk-Informed Extended Completion Times"

Reference:

Letter from T. McGinty and A. Boland (NRC) to Technical Specifications Task Force (TSTF), "Issues with Technical Specifications Task Force Traveler TSTF-505, Revision 1, 'Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b'," dated November 15, 2016 In the referenced letter, the NRC raised concerns with approved TSTF traveler, TSTF-505-A, Revision 1, "Provide Risk-Informed Extended Completion Times." The NRC published in the Federal Register a notice of availability for the Model Safety Evaluation (SE) for plant-specific adoption of TSTF traveler TSTF-505, Revision 1, on March 15, 2012. Currently, six licensees have License Amendment Requests (LARs) under NRC review to adopt risk-informed Completion Times.

On December 13, 2016, the TSTF and the Nuclear Energy Institute (NEI) met with the NRC to discuss the NRC's concerns. Most the NRC concerns were related to proposed Technical Specifications (TS) Actions related to all trains of a TS required system being inoperable (i.e.,

loss of function). The industry proposed the following short-term and long-term actions to resolve the NRC concerns:

1. The industry will pursue development of a companion traveler for TSTF-505 that addresses the NRC issues with Actions related to a loss of function. Following approval, plants that have adopted TSTF-505 without Actions related to a loss of function could submit a LAR to adopt the companion traveler. Following NRC approval of the companion traveler, plants that have not adopted TSTF-505 can adopt TSTF-505 and the companion traveler in a single LAR.

2. TSTF-505 allows licensees to choose which Action changes are included in their LAR. The TSTF will recommend to the industry that until the companion traveler is approved by the NRC, licensees submitting LARs to adopt TSTF-505 not include Action changes related to a loss of function. Omitting these Actions should allow timely approval of LARs and provide the majority of the benefit of TSTF-505. Attachment 1 contains a list of the Actions revised 11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Administration by EXCEL Services Corporation

DRAFT TSTF-17-01 DATE by TSTF-505 that should be omitted, as well as conforming changes to the TSTF-505 Section 1.3 TS example and the TS Section 5.5 Administrative Controls program.

3. The proposed actions only apply to future submittals. The licensees with LARs currently under NRC review will decide how to proceed.

The NRC had questions on other aspects of TSTF-505 not related to loss of function. Those questions are addressed in Attachment 2.

The TSTF requests that the NRC rescind the suspension of the approval of TSTF-505, Revision 1, and accept LARs to adopt TSTF-505 that do not include proposed Actions with risk-informed Completion Times related to loss of function, as described in Attachment 1. Following NRC approval of a TSTF traveler that addresses Actions with a risk-informed Completion Time related to loss of function, LARs should be accepted for review that propose to adopt TSTF-505 and the companion traveler.

Should you have any questions, please do not hesitate to contact us.

James R. Morris (PWROG/W) Lisa L. Williams (BWROG)

Otto W. Gustafson (PWROG/CE) Michael K. Leisure (PWROG/B&W)

Jason P. Redd (APOG)

Enclosure cc: Timothy J. McGinty, Director of the Division of Safety Systems Anne T. Boland, Director of the Division of Operating Reactor Licensing Alex Klein, Technical Specifications Branch Michelle Honcharik, Technical Specifications Branch

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function TSTF-505 Markup to NUREG-1430, Babcock and Wilcox STS Specification Specification Title Notes See attached recommended 1.3 Completion Times changes Action 3.3.1.C RPS Instrumentation LOF. Do not include Action 3.3.5.B ESFAS Instrumentation LOF. Do not include Action 3.3.6.B ESFAS Manual Initiation LOF. Do not include Action 3.3.11.D EFIC System Instrumentation LOF. Do not include Action 3.3.13.B EFIC Logic LOF. Do not include Action 3.3.14.B EFIC-EFW- Vector Valve Logic LOF. Do not include Action 3.5.1.A CFTs Do not include Action 3.5.1.C CFTs LOF. Do not include Action 3.5.2.C ECCS - Operating LOF. Do not include Action 3.5.4.A BWST Do not include Action 3.6.6.F Containment Spray and Cooling Systems LOF. Do not include Action 3.7.2.C MSIVs LOF. Do not include Action 3.7.5.C EFW System LOF. Do not include Action 3.7.8.B SWS LOF. Do not include Action 3.7.9.C UHS LOF. Do not include Action 3.7.11.B CREVS LOF. Do not include Action 3.8.1.G AC Sources - Operating LOF. Do not include Action 3.8.4.D DC Sources - Operating LOF. Do not include Action 3.8.7.B Inverters - Operating LOF. Do not include Action 3.8.9.D Distribution Systems - Operating LOF. Do not include See attached recommended 5.5.18 Risk Informed Completion Time Program changes Page 1

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function TSTF-505 Markup to NUREG-1431, Westinghouse STS Specification Specification Title Notes See attached recommended 1.3 Completion Times changes Action 3.3.1.C RTS Instrumentation LOF. Do not include Action 3.3.1.E RTS Instrumentation LOF. Do not include Action 3.3.1.G RTS Instrumentation LOF. Do not include Action 3.3.1.I RTS Instrumentation LOF. Do not include Action 3.3.1.Q RTS Instrumentation LOF. Do not include Action 3.3.1.T RTS Instrumentation LOF. Do not include Action 3.3.1.W RTS Instrumentation LOF. Do not include Action 3.3.1.Z RTS Instrumentation LOF. Do not include Action 3.3.1.CC RTS Instrumentation LOF. Do not include Action 3.3.1.EE RTS Instrumentation LOF. Do not include Action 3.3.1.JJ RTS Instrumentation LOF. Do not include Action 3.3.2.C ESFAS Instrumentation LOF. Do not include Action 3.3.2.E ESFAS Instrumentation LOF. Do not include Action 3.3.2.G ESFAS Instrumentation LOF. Do not include Action 3.3.2.I ESFAS Instrumentation LOF. Do not include Action 3.3.2.K ESFAS Instrumentation LOF. Do not include Action 3.3.2.M ESFAS Instrumentation LOF. Do not include Action 3.3.2.O ESFAS Instrumentation LOF. Do not include Action 3.3.2.Q ESFAS Instrumentation LOF. Do not include Action 3.3.2.S ESFAS Instrumentation LOF. Do not include Action 3.3.2.U ESFAS Instrumentation LOF. Do not include Action 3.3.9.B BDPS LOF. Do not include Action 3.4.9.C Pressurizer LOF. Do not include.

Action 3.5.1.A Accumulators Do not include.

Page 2

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function TSTF-505 Markup to NUREG-1431, Westinghouse STS Specification Specification Title Notes Action 3.5.1.C Accumulators LOF. Do not include.

Action 3.5.2.B ECCS - Operating LOF. Do not include.

Action 3.5.4.A RWST Do not include.

Containment Spray and Cooling Systems Action 3.6.6A.E (Atmospheric and Dual) LOF. Do not include.

Containment Spray and Cooling Systems Action 3.6.6B.G (Atmospheric and Dual) LOF. Do not include.

Action 3.6.6C.B Containment Spray System (Ice Condenser) LOF. Do not include.

Action 3.6.6D.B QS System (Subatmospheric) LOF. Do not include.

Action 3.6.6E.F RS System (Subatmospheric) LOF. Do not include.

Action 3.6.10.C HIS (Ice Condenser) LOF. Do not include.

Action 3.6.14.B ARS (Ice Condenser) LOF. Do not include.

Action 3.6.18.A Containment Recirculation Drains (Ice Condenser) LOF. Do not include.

Action 3.6.18.B Containment Recirculation Drains (Ice Condenser) LOF. Do not include.

Action 3.7.2.C MSIVs LOF. Do not include.

Action 3.7.5.C AFW System LOF. Do not include.

Action 3.7.7.B CCW System LOF. Do not include.

Action 3.7.8.B SWS LOF. Do not include.

Action 3.7.9.C UHS LOF. Do not include.

Action 3.7.11.B CREATCS LOF. Do not include.

Action 3.8.1.G AC Sources - Operating LOF. Do not include Action 3.8.4.D DC Sources - Operating LOF. Do not include Action 3.8.7.B Inverters - Operating LOF. Do not include Action 3.8.9.D Distribution Systems - Operating LOF. Do not include See attached Recommended 5.5.18 Risk Informed Completion Time Program Changes Page 3

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function TSTF-505 Markup to NUREG-1432, Combustion Engineering STS Specification Specification Title Notes See attached recommended 1.3 Completion Times changes Action 3.3.4.B ESFAS Instrumentation (Analog) LOF. Do not include.

Action 3.3.5.B ESFAS Logic and Manual Trip (Analog) LOF. Do not include.

Action 3.3.5.E ESFAS Logic and Manual Trip (Analog) LOF. Do not include.

Action 3.3.6.E ESFAS Logic and Manual Trip (Digital) LOF. Do not include.

Action 3.4.9.C Pressurizer LOF. Do not include.

Action 3.5.1.A SITs Do not include.

Action 3.5.1.C SITs LOF. Do not include.

Action 3.5.2.C ECCS - Operating LOF. Do not include.

Action 3.5.4.A RWT Do not include.

Containment Spray and Cooling Systems Action 3.6.6A.F (Atmospheric and Dual) LOF. Do not include.

Containment Spray and Cooling Systems Action 3.6.6B.F (Atmospheric and Dual) LOF. Do not include.

Action 3.7.2.C MSIVs LOF. Do not include.

Action 3.7.5.C AFW System LOF. Do not include.

Action 3.7.7.B CCW System LOF. Do not include.

Action 3.7.8.B SWS LOF. Do not include.

Action 3.7.9.C UHS LOF. Do not include.

Action 3.7.10.B ECW LOF. Do not include.

Action 3.7.12.B CREATCS LOF. Do not include.

Action 3.8.1.G AC Sources - Operating LOF. Do not include Action 3.8.4.D DC Sources - Operating LOF. Do not include Action 3.8.7.B Inverters - Operating LOF. Do not include Action 3.8.9.D Distribution Systems - Operating LOF. Do not include See attached recommended 5.5.18 Risk Informed Completion Time Program changes Page 4

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function TSTF-505 Markup to NUREG-1433, BWR/4 STS Specification Specification Title Notes See attached recommended 1.3 Completion Times changes Action 3.1.7.A SLC System Do not include.

Action 3.3.6.3.D LLS Instrumentation LOF. Do not include.

Action 3.4.3.B S/RVs LOF. Do not include.

Action 3.5.1.G ECCS - Operating LOF. Do not include.

Action 3.5.1.I ECCS - Operating LOF. Do not include.

Action 3.7.2.F [PSW] System and [UHS] LOF. Do not include.

Action 3.7.5.B [Control Room AC] System LOF. Do not include.

Action 3.8.1.G AC Sources - Operating LOF. Do not include Action 3.8.4.D DC Sources - Operating LOF. Do not include Action 3.8.7.B Inverters - Operating LOF. Do not include Action 3.8.9.D Distribution Systems - Operating LOF. Do not include See attached recommended 5.5.15 Risk Informed Completion Time Program changes Page 5

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function TSTF-505 Markup to NUREG-1434, BWR/6 STS Specification Specification Title Notes See attached recommended 1.3 Completion Times changes Action 3.1.7.A SLC System Do not include.

Action 3.3.6.5.B Relief and LLS Instrumentation LOF. Do not include.

Action 3.4.4.B S/RVs LOF. Do not include.

Action 3.5.1.G ECCS - Operating LOF. Do not include.

Action 3.5.1.I ECCS - Operating LOF. Do not include.

Action 3.5.1.J ECCS - Operating LOF. Do not include.

Action 3.5.1.K ECCS - Operating LOF. Do not include.

Action 3.5.1.L ECCS - Operating LOF. Do not include.

Action 3.6.2.4.D SPMU System LOF. Do not include.

Action 3.6.5.6.F Drywell Vacuum Relief System LOF. Do not include.

Action 3.7.1.D [SSW] System and [UHS] LOF. Do not include.

Action 3.7.4.B [Control Room AC] System LOF. Do not include.

Action 3.8.1.G AC Sources - Operating LOF. Do not include Action 3.8.4.D DC Sources - Operating LOF. Do not include Action 3.8.7.B Inverters - Operating LOF. Do not include Action 3.8.9.D Distribution Systems - Operating LOF. Do not include See attached recommended 5.5.15 Risk Informed Completion Time Program changes Page 6

Attachment 1 TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function DRAFT Recommended Changes to the Section 1.3 Example in TSTF-505

---

Reviewer's Note ------------------------------------------

Example 1.3-8 is only applicable to plants that have adopted the Risk Informed Completion Time Program.

[ EXAMPLE 1.3-8 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One subsystem A.1 Restore subsystem 7 days inoperable. to OPERABLE status. OR In accordance with the Risk Informed Completion Time Program B. --- NOTE ------ B.1 Restore subsystems 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Not applicable to OPERABLE when second status. OR subsystem intentionally In accordance with the made Risk Informed inoperable. Completion Time

---

Program Two subsystems inoperable.

BC.Required BC.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Action and associated AND Completion Time not met. BC.2 Be in MODE 5. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> When a subsystem is declared inoperable, Condition A is entered. The 7 day Completion Time may be applied as discussed in Example 1.3-2. However, the Page 7

Attachment 1 DRAFT TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function Recommended Changes to the Section 1.3 Example in TSTF-505 licensee may elect to apply the Risk Informed Completion Time Program which permits calculation of a Risk Informed Completion Time (RICT) that may be used to complete the Required Action beyond the 7 day Completion Time. The RICT cannot exceed 30 days. After the 7 day Completion Time has expired, the subsystem must be restored to OPERABLE status within the RICT or Condition BC must also be entered.

If a second subsystem is declared inoperable, Condition B may also be entered. The Condition is modified by a Note stating it is not applicable if the second subsystem is intentionally made inoperable. The Required Actions of Condition B are not intended for voluntary removal of redundant subsystems from service. The Required Action is only applicable if one subsystem is inoperable for any reason and the second subsystem is found to be inoperable, or if both subsystems are found to be inoperable at the same time. If Condition B is applicable, at least one subsystem must be restored to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or Condition C must also be entered. The licensee may be able to apply a RICT to extend the Completion Time beyond 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> if the requirements of the Risk Informed Completion Time Program are met. If two subsystems are inoperable and Condition B is not applicable (i.e., the second subsystem was intentionally made inoperable), LCO 3.0.3 is entered as there is no applicable Condition.

The Risk Informed Completion Time Program requires recalculation of the RICT to reflect changing plant conditions. For planned changes, the revised RICT must be determined prior to implementation of the change in configuration. For emergent conditions, the revised RICT must be determined within the time limits of the Required Action Completion Time (i.e., not the RICT) or 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after the plant configuration change, whichever is less.

If the 7 day Completion Time clock of Condition A or the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Completion Time clock of Condition B have has expired and subsequent changes in plant condition result in exiting the applicability of the Risk Informed Completion Time Program without restoring the inoperable subsystem to OPERABLE status, Condition BC is also entered and the Completion Time clocks for Required Actions BC.1 and BC.2 start.

If the RICT expires or is recalculated to be less than the elapsed time since the Condition was entered and the inoperable subsystem has not been restored to OPERABLE status, Condition BC is also entered and the Completion Time clocks for Required Actions BC.1 and BC.2 start. If the inoperable subsystems are restored to OPERABLE status after Condition BC is entered, Conditions A, B, and BC are exited, and therefore, the Required Actions of Condition BC may be terminated. ]

Page 8

Attachment 1 TSTF-505 Recommended Changes to Exclude Provisions Related to Loss of Function DRAFT Recommended Changes to the Risk Informed Completion Time Program in TSTF-505

[ 5.5.18 Risk Informed Completion Time Program This program provides controls to calculate a Risk Informed Completion Time (RICT) and must be implemented in accordance with NEI 06-09-A, Revision 0, "Risk-Managed Technical Specifications (RMTS) Guidelines." The program shall include the following:

a. The RICT may not exceed 30 days;

---

REVIEWER'S NOTE ----------------------------------

The Risk Informed Completion Time is only applicable in MODES supported by the Licensees PRA. Licensee's applying the RICT Program to MODES other than Modes 1 and 2 must demonstrate that they have the capability to calculate a RICT in those MODES or that the risk indicated by their MODE 1 and 2 PRA model is bounding with respect to the lower MODE conditions.

b. A RICT may only be utilized in MODE 1, 2 [, and 3, and MODE 4 while relying on steam generators for heat removal];

c. When a RICT is being used, any plant configuration change within the scope of the Risk Informed Completion Time Program must be considered for the effect on the RICT.

1. For planned changes, the revised RICT must be determined prior to implementation of the change in configuration.

2. For emergent conditions, the revised RICT must be determined within the time limits of the Required Action Completion Time (i.e., not the RICT) or 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after the plant configuration change, whichever is less.

3. Revising the RICT is not required If the plant configuration change would lower plant risk and would result in a longer RICT.

d. Use of a RICT is not permitted for voluntary entry into a configuration which represents a loss of a specified safety function or inoperability of all required trains of a system required to be OPERABLE.

e. Use of a RICT is permitted for emergent conditions which represent a loss of a specified safety function or inoperability of all required trains of a system required to be OPERABLE if one or more of the trains are considered "PRA functional" as defined in Section 2.3.1 of NEI 06-09.]

Page 9

Attachment 2 DRAFT Response to NRC Questions on TSTF-505 Not Related to Loss of Function Provisions

1. At the December 13, 2016, public meeting, the NRC asked for more information on the inclusion of a Risk Informed Completion Time (RICT) provision for Required Actions that do not require restoration of the system to Operable status.

Response

At a September 8, 2010, public meeting between the NRC and the TSTF to discuss TSTF-505, the NRC raised concerns with including changes in TSTF-505 that were not in the South Texas Project (STP) lead plant submittal scope of applying a RICT to Required Actions that either 1) require restoring the inoperable system to operable status, 2) require placing an instrument channel in trip, or 3) require isolating a containment isolation valve. As a result, Revision 1 of TSTF-505 removed changes that did not fall into these categories.

In a Request for Additional Information (RAI) on TSTF-505 dated July 27, 2010, the NRC questioned the calculation of a RICT for placing a channel in trip or bypass. The TSTF agreed to remove changes applying a RICT to placing a channel in bypass, and justified applying a RICT for placing a channel in trip. The RAI response stated:

The TSTF believes that the TSTF-505 option to calculate a RICT for placing channels in trip should be retained. The NRC has reviewed and approved risk-based Topical Reports that change the Completion Time for placing a channel in trip, such as WCAP-14333, "Probabilistic Risk Analysis of the RPS and ESFAS Test Times and Completion Times,"

approved July 15, 1998. A licensee could choose to model these actions and calculate a RICT for placing a channel in trip.

The NRC approved TSTF-505 with provisions to calculate a RICT for Required Actions that require placing a channel in trip.

2. At the December 13, 2016, public meeting, the NRC asked for an explanation of the difference between the TSTF-505 RICT program and the NEI 06-09 Configuration Risk Management Program.

Response

The TSTF-505 justification, Section 2.0, "Proposed Change," states:

There is a new Chapter 5 Program entitled, "Risk Informed Completion Time Program" which is invoked when utilizing a RICT. In NEI 06-09 this program is called the Configuration Risk Management Program. That title is not used in the Traveler because some licensees already have a Chapter 5 program of that name serving a different purpose and the proposed name is more descriptive of the purpose of the new program.

Therefore, the TSTF-505 Risk Informed Completion Time program is the same as the NEI 06-09 Configuration Risk Management Program.

Page 1

Attachment 2 DRAFT Response to NRC Questions on TSTF-505 Not Related to Loss of Function Provisions

3. At the December 13, 2016, public meeting, the NRC asked for a more detailed discussion regarding treatment of common cause failure term adjustments when calculating a RICT.

Response

The NEI 06-09 and the associated safety evaluation state that common cause must be considered for emergent failures and require consideration and implementation of Risk Management Actions (RMAs) to address the risk of potential common cause failures as identified by the extent of condition evaluation.

The last paragraph of section 2.3.1 of NEI 06-09 states:

15. Operability determinations should follow regulatory guidance established in Part 9900 of the NRC Inspection Manual [9]. RMAT and RICT calculations performed for emergent conditions shall be performed assuming that all equipment not declared inoperable during the operability determination process are functional. However, the station shall establish appropriate RMAs based on an assessment of the potential for increased risks due to common cause failure of similar equipment. (Note that if there is not evidence for increased potential for common cause failures, no RMAs are required).

The safety evaluation for NEI 06-09, in the section titled "emergent failures," states:

Emergent Failures. During the time when an RICT is in effect and risk is being assessed and managed, it is possible that emergent failures of SSCs may occur, and these must be assessed to determine the impact on the RICT. If a failed component is one of two or more redundant components in separate trains of a system, then there is potential for a common cause failure mechanism. Licensees must continue to assess the remaining redundant components to determine there is reasonable assurance of their continued operability, and this is not changed by implementation of the RMTS. If a licensee concludes that the redundant components remain operable, then these components are functional for purposes of the RICT. However, the licensee is required to consider and implement additional risk management actions (RMAs), due to the potential for increased risks from common cause failure of similar equipment. The staff interprets TR NEI 06-09, Revision 0, as requiring consideration of such RMAs whenever the redundant components are considered to remain operable, but the licensee has not completed the extent of condition evaluations, and additionally, as required by a follow-up prompt operability determination. (emphasis added)

NEI 06-09 includes the following guidance on consideration of common cause failures:

3.3.6 Common Cause Failure Consideration Common cause failures are required to be considered for all RICT assessments. For all RICT assessments of planned configurations, the treatment of common cause failures in the quantitative CRM Tools may be performed by considering only the removal of the planned equipment and not adjusting common cause failure terms. For RICT assessments involving unplanned or emergent conditions, the potential for common cause failure is Page 2

Attachment 2 DRAFT Response to NRC Questions on TSTF-505 Not Related to Loss of Function Provisions considered during the operability determination process. This assessment is more accurately described as an "extent of condition" assessment. Licensed operators recognize that an emergent condition identified on a Technical Specifications component may have the potential to affect a redundant component or similar components. In addition to a determination of operability on the affected component, the operator should make a judgment with regard to whether the operability of similar or redundant components might be affected. In accordance with the operability determination guidance in Part 9900 of the NRC Inspection Manual (provided in Regulatory Information Summary 2005-20), the determination of operability should be done promptly, commensurate with the safety significance of the affected component. If a common condition affects the operability of multiple components (e.g., that more than one common cause group functional train is affected), action should be taken via the Technical Specifications. Based on the information available, the licensed operator is often able to make an immediate determination that there is reasonable assurance that redundant or similar components are not affected. Using judgment with regard to the specific condition, the operator may direct that similar or redundant components be inspected for evidence of the degradation. For conditions where the operator has less information, assistance from other organizations, such as Station Engineering, is typically requested. These support organizations continue to perform the evaluation promptly, as described above. The guidance contained in Part 9900 of the Inspection Manual is used as well as conservative decision-making for extent of condition evaluations. The components are considered functional in the PRA unless the operability evaluation determines otherwise.

While quantitative changes to the PRA are not required, the PRA should be used as appropriate to provide insights for the qualitative treatment of potential common cause failures and RMAs that may be applied for the affected configuration. Such information may be used in prioritizing the repair, ensuring proper resource application, and taking other compensatory measures as deemed prudent by station management."

NRC Regulatory Guide 1.177, "An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications," addresses common cause failure treatment for risk-informed changes to Technical Specifications. Appendix A, Section 1.3.1.1, discusses quantitative adjustment of the common cause failure probabilities based on the cause of the equipment unavailability. Section 2.3 of the Regulatory Guide states that Appendix A outlines issues associated with Tier 1. Tier 1 is an assessment of the risk impact of a proposed change that is submitted to the NRC as part of a license amendment request. This is contrasted with Tier 3, which is a contemporaneous configuration risk management risk assessment performed by the licensee while the equipment is out of service.

As noted in NEI 06-09, Section 1.1, and throughout the document, the assessment and management of configuration-specific risk is within the context of a configuration risk management program, and the RICT is required to be re-calculated for any configuration changes. Since common cause failure quantitative adjustments are explicitly excluded from Tier 3 methods in Regulatory Guide 1.177 and since the RICT calculations are configuration risk Page 3

Attachment 2 DRAFT Response to NRC Questions on TSTF-505 Not Related to Loss of Function Provisions assessments associated with Tier 3 assessments, these quantitative adjustments are not applicable to calculating a RICT.

Therefore, the RICT process explicitly addresses common cause failure and mitigates the associated risk by development and implementation of RMAs specifically targeted toward common cause failure, consistent with regulatory guidance.

4. At the December 13, 2016, public meeting, the NRC asked for a discussion regarding the differences between the Risk Informed Completion Time Program and the 10 CFR 50.65 Maintenance Rule program.

Response

Most TS provide a Completion Time during which the LCO may not be met to permit a licensee to perform required testing, maintenance, or repair activities. Normally, upon expiration of the Completion Time, the requirement to shut down the reactor or follow remedial action is imposed. NEI 06-09 provides a means for the licensee to extend the Completion Time and thereby delay reactor shutdown or remedial actions, if risk is assessed and managed within specified limits and programmatic requirements established by the TS. The regulatory requirements for the content of LCOs will continue to be met, since only the Completion Time is changed. The specific functional capabilities or performance levels of equipment required by the safety analyses are unchanged, and the remedial actions, including the requirement to shut down the reactor, are also unchanged; only the specific time limits for initiating actions are extended by the methodology documented in NE1 06-09.

The maintenance rule, 10 CFR 50.65, "Requirements for monitoring the effectiveness of maintenance at nuclear power plants," requires licensees to monitor the performance or condition of structures, systems and components (SSCs) against licensee-established goals in a manner sufficient to provide a reasonable assurance that these SSCs are capable of fulfilling their intended functions. In addition, 10 CFR 50.65(a)(4) requires the assessment and management of the increase in risk that may result from a proposed maintenance activity. The methodology in NE1 06-09 uses processes that are complementary to the requirements of 10 CFR 50.65(a)(4).

Both processes recognize that plant risk is increased when equipment is out of service. Both processes take actions commensurate with the risk due to the specific configuration. If a system is addressed in the Technical Specifications any work performed under the Maintenance Rule program is performed within the constraints of the TS completion time. The RICT program allows the completion time available to perform work to potentially be adjusted within the constraints of the program and plant configuration. Thus, the two programs are interrelated and implementation of the RICT program builds on the existing Maintenance Rule configuration control process.

5. At the December 13, 2016, public meeting, the NRC questioned applying a RICT to existing TS Actions that appeared to be a loss of function. In particular, the staff questioned calculating a RICT for the existing Actions for two inoperable emergency diesel generators and two inoperable offsite circuits.

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Attachment 2 DRAFT Response to NRC Questions on TSTF-505 Not Related to Loss of Function Provisions

Response

The ISTS defines "operable/operability" as:

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).

(emphasis added)

In order to be operable, a system must have either normal electrical power (offsite circuits) or emergency electrical power (emergency diesel generators). Losing one power source does not render the supported systems inoperable. TS 3.8.1, "AC Sources - Operating," contains requirements on both the offsite circuits and the emergency diesel generators because either system can perform the safety function.

TS Administrative Controls Section 5.5, "Safety Function Determination Program," defines a loss of safety function. It states:

A loss of safety function exists when, assuming no concurrent single failure, no concurrent loss of offsite power, or no concurrent loss of onsite diesel generator(s), a safety function assumed in the accident analysis cannot be performed.

Under this TS definition, a single offsite circuit or a single emergency diesel generator can perform the safety function. Therefore, the existing TS 3.8.1 Actions for two inoperable offsite circuits (Action C) or two inoperable diesel generators (Action E) do not represent a loss of safety function. This is consistent with the TS Bases. The Bases for Condition H, which is applicable when three or more required AC sources are inoperable, states, "Condition H corresponds to a level of degradation in which all redundancy in the AC electrical power supplies has been lost. At this severely degraded level, any further losses in the AC electrical power system will cause a loss of function" (emphasis added). In other words, a loss of safety function occurs when there is no operable offsite circuits or emergency diesel generators.

Therefore, a RICT can be calculated for two inoperable offsite circuits (Condition C) or two inoperable emergency diesel generators (Condition E) without considering PRA Functionality or a loss of function.

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