Reports and guidance documents; availability, etc.: Combustion engineering pressurized water reactors; containment spray and cooling systems; technical specification improvement; model safety evaluation,

[Federal Register: November 7, 2006 (Volume 71, Number 215)]

[Notices]

[Page 65148-65160]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr07no06-79]

NUCLEAR REGULATORY COMMISSION

Notice of Availability of Model License Amendment Request and Safety Evaluation on Technical Specification Improvement Regarding Revision to the Completion Time in STS 3.6.6A, ``Containment Spray and Cooling Systems'' for Combustion Engineering Pressurized Water Reactors Using the Consolidated Line Item Improvement Process

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of availability.

SUMMARY: Notice is hereby given that the staff of the U.S. Nuclear Regulatory Commission (NRC) has prepared a model license amendment request (LAR), model safety evaluation (SE), and model proposed no significant hazards consideration (NSHC) determination related to changes to the completion times (CT) in Standard Technical Specification (STS) 3.6.6A, ``Containment Spray and Cooling Systems,'' contained in NUREG-1432 (Standard Technical Specifications for Combustion Engineering Plants, Rev. 3.0). The proposed changes would revise STS 3.6.6A by extending the CT for one containment spray system (CSS) train inoperable from 72 hours to seven days, and add a Condition, Required Actions and associated CT when one CSS train and one containment cooling system (CCS) train are inoperable. These changes are based on analyses provided in a joint applications report submitted by the Combustion Engineering Owner's Group (CEOG). The CEOG participants in the Technical Specifications Task Force (TSTF) proposed these changes to the STS in Change Traveler No. TSTF-409, Revision 2.

The purpose of these models is to permit the NRC to efficiently process amendments to incorporate these changes into plant-specific STS for Combustion Engineering pressurized water reactors (PWRs). Since TSTF-409 involves a risk-informed approach to extending the CT for one CSS inoperable, the NRC staff must verify that licensees who apply for this TS change have a valid, up-to-date probabilistic risk assessment (PRA) model that employs PRA principles to ensure that public health and safety are maintained when the CSS CT of 7 days is implemented. Therefore, the model LAR contains several conditions requiring licensees to make specific validations of their plant PRA quality and methods. The intent of using the CLIIP to adopt TSTF-409 is to eliminate

[[Page 65149]]

the need for additional technical review and requests for additional information (RAIs) on plant-specific amendments. Licensees of nuclear power reactors to which the models apply can request amendments conforming to the models. In such a request, a licensee should confirm the applicability of the model SE and NSHC determination to its plant, and provide the expected supplemental information requested in the model LAR.

DATES: The NRC staff issued a Federal Register Notice (71 FR 18380, April 11, 2006) which provided for public comment a model SE, model LAR, and NSHC determination related to changes to the CT for one CSS train inoperable in STS 3.6.6A. The NRC staff herein provides a revised model SE, revised model LAR, and NSHC determination. The NRC staff can most efficiently consider applications based upon the model LAR, which references the Model SE, if the application is submitted within one year of this Federal Register Notice.

FOR FURTHER INFORMATION CONTACT: Tim Kobetz, Mail Stop: O-12H2, Division of Inspection Program Management, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555- 0001, telephone 301-415-1932.

SUPPLEMENTARY INFORMATION:

Background

Regulatory Issue Summary 2000-06, ``Consolidated Line Item Improvement Process [CLIIP] for Adopting Standard Technical Specifications Changes for Power Reactors,'' was issued on March 20, 2000. The CLIIP is intended to improve the efficiency and transparency of NRC licensing processes. This is accomplished by processing proposed changes to the STS in a manner that supports subsequent license amendment applications. The CLIIP includes an opportunity for the public to comment on proposed changes to the STS following a preliminary assessment by the NRC staff and finding that the change will likely be offered for adoption by licensees. The CLIIP includes NRC staff evaluation of any comments received for a proposed change to the STS. In several instances, the staff's evaluation did result in changes to the model LAR and/or model SE. Those licensees opting to apply for the subject changes to TSs are responsible for reviewing the staff's evaluation, referencing the applicable technical justifications, and providing any necessary plant-specific information. The model LAR shows licensees the expected level of detail that needs to be included in order to adopt TSTF-409, Rev. 2, as well as guidelines for staff review. The NRC has established an internal review plan that designates the appropriate staff and approximate timelines to review plant-specific LARs that reference TSTF-409, Rev. 2. Each amendment application made in response to the notice of availability will be processed and noticed in accordance with applicable NRC rules and procedures.

This notice involves an increase in the allowed CT to restore an inoperable CSS train on Combustion Engineering PWRs. By letter dated November 10, 2003, the CEOG proposed this change for incorporation into the STS as TSTF-409, Revision 2. This change is based on the NRC staff- approved analyses contained in CE NPSD-1045-A, ``Joint Applications Report: Modification to the Containment Spray System, and Low Pressure Safety Injection System Technical Specifications,'' dated March 2000, as approved by the NRC in a SE dated December 21, 1999, accessible electronically from the Agencywide Documents Access and Management System's (ADAMS) Public Electronic Reading Room on the Internet (ADAMS Accession No. ML993620241) at the NRC Web site http://www.nrc.gov/reading-rm/adams.html. Persons who do not have access to ADAMS or who

encounter problems in accessing the documents located in ADAMS, should contact the NRC Public Document Room Reference staff by telephone at 1- 800-397-4209, 301-415-4737, or by e-mail to pdr@nrc.gov.

This notice, along with TSTF-409, Rev. 2, will be posted on the NRC Web site at http://www.nrc.gov/reactors/operating/licensing/techspecs/changes-issued-for-adoption.html .

Applicability

This proposed change to revise the Technical Specification (TS) CT for one inoperable CSS train is applicable to Combustion engineering PWRs.

To efficiently process the incoming license amendment applications, the NRC staff requests that each licensee applying for the changes addressed by TSTF-409, Revision 2, use the CLIIP to submit a LAR that adheres to the following model. Any deviations from the model LAR should be explained in the licensee's submittal. When applying, licensees should ensure they address the eight conditions and one regulatory commitment listed in the model LAR and model SE.

The CLIIP does not prevent licensees from requesting an alternative approach, proposing changes without providing the information described in the eight model LAR conditions, or making the requested commitment. Variations from the approach recommended in this notice may, however, require additional review by the NRC staff and may increase the time and resources needed for the review. Significant variations from the approach, or inclusion of additional changes in the LAR, will result in staff rejection of the submittal under the CLIIP. Instead, licensees desiring significant variations and/or additional changes should either submit a LAR that does not claim to adopt TSTF-409, or specifically state in their LAR that they are adopting TSTF-409 without using the CLIIP.

Public Notices

In a notice in the Federal Register dated April 11, 2006 (71 FR 18380), the staff requested comment on the use of the CLIIP to process requests to revise the CE PWR TS regarding Containment Spray System completion time extensions as discussed in TSTF-409. In response to this notice, the staff received one set of comments (developed by the PWR Owners Group, and submitted by the Nuclear Energy Institute in a letter dating May 10, 2006 (ADAMs Accession No. ML061570029)). Specific comments on the model LAR and model SE were offered. These comments, along with the NRC staff's responses, are summarized and discussed below.

1. Comment: Based on discussions with the author regarding the intent of the ``Model SE,'' [i.e., to allow acceptance review without RAIs while satisfying the CLIIP] it is recommended that additional explanatory information be included. * * * At the very minimum, a clear preamble to the FRN should be provided that places the scope of the FRN in perspective.

   Response: The following preamble has been inserted after the first sentence of the second paragraph of the FRN.

   ``Since TSTF-409 involves a risk-informed approach to extending the CT for one CSS inoperable, the NRC staff must verify that licensees who apply for this TS change have a valid, up to date probabilistic risk assessment (PRA) model that employs PRA principles to ensure that public health and safety are maintained when the CSS CT of 7 days is implemented. Therefore, the model LAR contains several conditions requiring licensees to make specific validations of their plant PRA quality and methods. The intent of using the CLIIP to adopt TSTF-409 is to eliminate the need for additional technical review and requests for additional information (RAIs) on plant-specific amendments.''

2. Comment: [The FRN] should equally note that existing strategies for

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   approval are valid and may also be used.

   Response: The second to last paragraph of the FRN discusses how a licensee should proceed if it desires to deviate from the approach outlined in the CLIIP. The NRC's position is that, if a licensee is going to submit a LAR that adopts TSTF-409 using the CLIIP, then the plant-specific LAR should provide all the information requested in the model LAR. Any variations/deviations should be explained, and may require additional review by the staff (including issuance of RAIs). Significant variations from the CLIIP methodology should be submitted as normal license amendment requests. The staff has changed the last sentence of second to last paragraph of the FRN to read:

   ``Instead, licensees desiring significant variations and/or additional changes should either submit a LAR that does not claim to adopt TSTF-409, or specifically state in their LAR that they are adopting TSTF-409 without using the CLIIP.''

   This will correctly define the scope of the review for the staff when processing an incoming LAR that does not conform to the CLIIP.

3. Comment: The essence of the proposed CSS TS change focuses on a single CSS train. Thus, the mention of ACTION G (regarding two CSS trains out-of-service) seems unnecessary.

   Response: The staff agrees with this comment. Mention of ACTION G has been removed from Section 4.1 of the model LAR, and Section 3.1 of the model SE.

4. Comment: The last paragraph of section 4.2.1 item 1 notes that ``If a zero maintenance PRA model is used * * * in performing these calculations, then the licensee must commit to performing no other maintenance during the extended CSS CT * * *''. This restriction has no technical merit. The risk of maintenance is generated as incremental risks from the baseline. The initial submittal noted that for plants with emergency grade fan coolers (most of the applicants), the actual risk increases as a result of removing a CSS out of service is very low. Furthermore, CSS have very little (if any) overlap with other systems. Because the risk important function of CSSs is to maintain the containment pressure within acceptable limits (and control sump temperature to ensure adequate NPSH for ECCS equipment--a function left out of FRN Section 3), those functions can be accommodated by the redundant CS train or the fan coolers. Furthermore, by using RG 1.177 to support low risk, the risk impact of removal of the CSS for the duration of the 7 day AOT is small. Because plants perform maintenance on a frequent basis, not allowing repair or maintenance on another system (which is likely to be of greater risk importance than the CSS) is unnecessary and likely to have worse risk.

   Another unusual aspect of the restriction implies that the incremental risk calculated using zero maintenance conditions is significantly different from that calculated using annualized plant- wide system out-of-service values. While the baseline PRA for zero maintenance is less than the baseline PRA value for nominal maintenance, its impact on incremental risk will be small.

   Response: The staff accepts NEI's comment in that it creates a regulatory condition that is overly restrictive to plants using a zero maintenance PRA model. The staff has inserted alternate wording (from RG 1.177 Section 2.3.4. 2) to the last sentence of condition 1 in Section 4.2.1 of the model LAR as follows:

   If the licensee utilizes a ``zero maintenance'' PRA model for the assessment, they should state they are using a ``zero maintenance'' model in the evaluation, and provide a discussion as to the ability of that model to produce comparable results to the ``average maintenance'' assessment.

5. Comment: It is understood that documented quantitative external event information for the plants may be limited. However, reference to plant individual plant examination (IPE) and individual plant examination for external events (IPEEE) and the requirements to explain the evolution of the PRA since 1988 as identified in Section in item 4.2.1 part 2.b is unnecessary. Item 2.c requires that the peer review results be discussed along with the overall disposition of relevant facts and observations (F&Os) and item e (which includes an overall determination of the adequacy of the plant specific PRA with respect to this application). These assessment[s] are current and of more importance to the application. Where external events rely on IPEEE vintage information, a discussion/statement of the risk significance of the spray system in mitigating external events should be performed.

   Response: The staff agrees that peer reviews of plant-specific PRA are important. However, it is equally important to have an understanding of PRA updates and upgrades since the IPE, IPEEE, and peer reviews were conducted, especially if plant improvements and/or commitments are cited and credited in the analyses as being implemented. Licensees who have given this information in prior submittals may incorporate the information by reference.

6. Comment: Section 4.2.1 item 3 requirements on consideration of fire and external events and the associated EXPECTATIONS are too restrictive and do not correspond to safety benefits. The CSS has limited risk overlap with fires or external initiating events. Challenges to power induced by tornadoes, high winds or seismic events have limited importance to the spray system and [are] more appropriate with AOTs associated with AC-power related components. It was our understanding that the intent of this restriction was to assure the regulator that the overall combined plant risk remains below a CDF of 10 -4per year (per requirements of RG 1.174). The intent of this section should be clarified. This requirement should be reduced to providing information regarding the reasons underlying low risk associated with this system.

   Response: The staff acknowledges that, for many plants, the impact of the CT extension on external event risk will be minimal. If this is the case, the licensee needs to confirm this in its submittal and explain why there is limited overlap.

7. Comment: Section 4.2.1 item 3 ACCEPTANCE CRITERIA requires ``combining internal events, internal flooding, external events and shutdown PRA results.'' The requirements for the combination of events should be modified to have the utility provide a technical basis for demonstrating the plant CDF to be less than 10 -4per year or has no plant specific vulnerabilities (per SECY-88-20). Requirements for a fully quantified external events (including fire) PRA and shutdown PRA [are] beyond the state of the art. Few plants have all the above. The Fire PRA standard is just undergoing peer review and no shutdown PRA standard has been written. Methods for combining these PRA results [are] also not defined (particularly merging shutdown and ``at power'' PRA results). Instead, it should be noted that the utility may use existing external event evaluations including IPEEE results and qualitative external event assessments, where appropriate, to provide confidence that the overall plant CDF is not within RG 1.174 risk region 1.

   Response: The staff is requesting that licensees provide [Delta]CDF and [Delta]LERF calculations for those external events for which the licensee has a PRA. For external events for which the licensee does not have a PRA, the licensee will need to confirm there are no vulnerabilities that would indicate that

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   the total CDF is >10-4or the total LERF is >10-\5\ yr. this stipulation allows the staff to ensure that plans whose [Delta]CDF or [Delta]LERF calculation puts them in Region II of either Figure 3 or Figure 4 of RG 1.174 are still within the RG 1.174 Section 2.2.4 acceptance guidelines for total plant risk (CDF and LERF).

   With regard to NEI's comments on a fully-quantified external events (including fire) PRA and shutdown PRA being beyond state-of-the-art, the staff believes the wording in the EXPECTATIONS for Section 4.2.1 condition 3 was misinterpreted. The wording has been revised to read ``(quantitatively and/or qualitatively, as appropriate).'' However, the staff notes that while fire and shutdown PRA standards have not yet been endorsed, there are available methods to quantify fire and shutdown PRA. Therefore, the staff does not believe such evaluations are beyond the state of the art. Rather, they are areas where some evaluation is still ongoing.

8. Comment: EXPECTATIONS supporting 4.2.1 item 4. The TS is structured to have a revised CT. Once the new CT is adopted the old CT will disappear as a regulatory item. Thus, there is no entry into an extended CSS CT. It is simply an entry into the CT. There are no significant external event interactions and the outage is limited to a single spray train. Therefore, The Tier 2 requirement should be limited to one CSS out of service, which is already governed in the TS with a cautionary note that Maintenance rule or tier 3 guidance to not simultaneously disable both the emergency grade fan coolers and the sprays.

   Response: The staff agrees that ``extended CT'' should not be used in the model LAR. Appropriate changes will be made here and in other sections of the FRN where appropriate.

   The staff believes that a tier 2 justification by the licensee is warranted with regard to removing one CSS train from service due to scheduled ``preventive'' maintenance for the 7-day period. If there are no risk-significant configurations or risk-significant external event conditions identified in the tier 2 evaluation, then the licensee should include a statement that there are no risk-significant configurations or external event conditions that would preclude them from using the 7-day CT.

9. Comment: End of [Section 4.2.1 item 7]. Note that the RGs provide guidelines. Risk values are not rigid thresholds. Thus small deviations to the guidance can be and are somewhat fuzzy to allow for the mathematical uncertainties inherent in these studies.

   Response: The staff agrees that RG 1.174 and 1.177 guidelines are not rigid standards, and has revised condition 7 to delete the second paragraph of the EXPECTATIONS section. Note that Condition 5 of the model LAR requires licensees to confirm that their CRMP or associated (a)(4) program meets all aspects of Section 2.3.7.2 or RG 1.177.

   Dated at Rockville, Maryland; this 19th day of October 2006.

   For the Nuclear Regulatory Commission. Timothy J. Kobetz, Branch Chief, Technical Specifications Branch, Division of Inspection and Regional Support, Office of Nuclear Reactor Regulation.

   FOR INCLUSION ON THE TECHNICAL SPECIFICATION WEB PAGE THE FOLLOWING EXAMPLE OF A LICENSE AMENDMENT REQUEST (LAR) WAS PREPARED BY THE NRC STAFF TO FACILITATE THE ADOPTION OF TECHNICAL SPECIFICATIONS TASK FORCE (TSTF) TRAVELER TSTF-409, REVISION 2 ``CONTAINMENT SPRAY SYSTEM COMPLETION TIME EXTENSION (CE NPSD-1045-A).'' THE MODEL PROVIDES THE EXPECTED LEVEL OF DETAIL AND CONTENT FOR A LAR TO ADOPT TSTF-409, REVISION 2. LICENSEES REMAIN RESPONSIBLE FOR ENSURING THAT THEIR PLANT- SPECIFIC LAR FULFILLS THEIR ADMINISTRATIVE REQUIREMENTS AS WELL AS NRC REGULATIONS.

   [fxsp0]

   U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

   SUBJECT: [PLANT NAME] APPLICATION FOR TECHNICAL SPECIFICATION IMPROVEMENT TO EXTEND THE COMPLETION TIME FOR CONTAINMENT SPRAY SYSTEM INOPERABILITY IN ACCORDANCE WITH TSTF-409, REVISION 2

   Dear Sir or Madam:

   In accordance with the provisions of Section 50.90 of Title 10 of the Code of Federal Regulations (10 CFR 50.90), [LICENSEE] is submitting a request for an amendment to the technical specifications (TS) for [PLANT NAME, UNIT NOS.].

   The proposed changes would revise TS 3.6.6A, ``Containment Spray and Cooling Systems,'' by extending from 72 hours to seven days the completion time (CT) to restore an inoperable containment spray system (CSS) train. In addition, a Condition would be added to the TS to allow one CSS train and one containment cooling system (CCS) train to be inoperable for a period of 72 hours.

   The changes are consistent with NRC-approved Industry Technical Specification Task Force (TSTF) Standard Technical Specification Change Traveler, TSTF-409, Revision 2, ``Containment Spray System Completion Time Extension (CE NPSD-1045-A).''

   Enclosure 1 provides a description and assessment of the proposed changes and confirmation of applicability. Enclosure 2 provides the existing TS pages marked-up to show the proposed changes. Enclosure 3 provides the existing TS Bases marked-up to reflect the proposed changes (for information only). Final TS Bases will be provided in a future update to the Updated Final Safety Analysis Report (UFSAR) in accordance with the Bases Control Program. Attachments 1 through 8 provide the discussions of [LICENSEE'S] evaluations and supporting information with regard to the conditions stipulated in Section 4.2.1 of Enclosure 1.

   [LICENSEE] requests approval of the proposed license amendment by

   [DATE] , with the amendment being implemented [BY DATE OR WITHIN X DAYS]. in accordance with 10 CFR 50.91, a copy of this application, with enclosures, is being provided to the designated [STATE] Official.

   I declare under penalty of perjury under the laws of the United States of America that I am authorized by [LICENSEE] to make this request and that the foregoing is true and correct. [Note that request may be notarized in lieu of using this oath or affirmation statement]. If you should have any questions regarding this submittal, please contact [ ].

   Sincerely,

   Name, Title

   Enclosures:

1. Description and Assessment of Proposed Changes

2. Proposed Technical Specification Changes

3. Proposed Technical Specification Bases Changes (if applicable)

   Attachments:

1. Licensee's supporting information for condition 1

2. Licensee's supporting information for condition 2

3. Licensee's supporting information for condition 3

4. Licensee's supporting information for condition 4

5. Licensee's supporting information for condition 5

6. Licensee's supporting information

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   for condition 6

7. Licensee's supporting information for condition 7

8. Licensee's supporting information for condition 8

   cc:

   NRR Project Manager

   Regional Office

   Resident Inspector

   State Contact

   ITSB Branch Chief

   1.0 Description

   The letter is a request to amend Operating License(s) [LICENSE NUMBER(S)] for [PLANT/UNIT NAME(S)].

   The proposed changes would revise Technical Specification (TS) 3.6.6A, ``Containment Spray and Cooling Systems,'' by extending from 72 hours to seven days the completion time (CT) to restore an inoperable containment spray system (CSS) train to operable status, and would add a Condition describing the required action and CT when one CSS train and one containment cooling system (CCS) train are inoperable.

   The changes are consistent with NRC approved Industry Owner's Group Technical Specification Task Force (TSTF) Standard Technical Specification Change Traveler TSTF-409, Revision 2 (Rev. 2), ``Containment Spray System Completion Time Extension (CE NPSD-1045- A).'' TSTF-409, Rev. 2 was approved by the NRC on [DATE].

   2.0 Proposed Change

   Specifically, the proposed revision extends the CT (or allowed outage time) that one CSS train is permitted to remain inoperable from 72 hours to seven days based on Reference 1, as accepted by, and subject to the limitations specified in, Reference 2. TSTF-409, Rev. 2 states that the longer CT will enhance overall plant safety by avoiding potential unscheduled plant shutdowns and allowing greater availability of safety significant components during shutdown. In addition, TSTF- 409, Rev. 2 states that this extension provides for increased flexibility in scheduling and performing maintenance and surveillance activities in order to enhance plant safety and operational flexibility during lower modes of operation.

   The revision also adds a Condition to allow one CSS train and one CCS train to be inoperable for up to 72 hours. Since Reference 1 did not evaluate the concurrent inoperabilities of one CSS train and one CCS train, the CT for this Condition was limited to 72 hours.

   [LICENSEE] also proposes to make changes to the supporting TS Bases in accordance with TSTF-409, Rev. 2. Changes to the Bases include supporting information justifying the addition of the Condition for one CSS train and one CCS train inoperable. The Bases changes also include a reviewer's note that requires [LICENSEE] to adopt Reference 1 and meet the requirements of References 1 and 2 prior to utilizing the 7- day CT for one inoperable CSS. Finally, a reference to Reference 1 is added to the Bases. Markups of the TS Bases are provided in enclosure 3. Changes to the Bases will be implemented in accordance with

   [LICENSEE's] bases control program.

   In summary, [LICENSEE] proposes to extend the CT for one inoperable CSS train from 72 hours to 7 days based on Reference 1, and add a Condition to allow one CSS train and one CCS train to be inoperable for up to 72 hours.

   3.0 Background

   The function of the containment heat removal systems under accident conditions is to remove heat from the containment atmosphere, thus maintaining the containment pressure and temperature at acceptably low levels. The systems also serve to limit offsite radiation levels by reducing the pressure differential between the containment atmosphere and the external environment, thereby decreasing the driving force for fission product leakage across the containment. The two containment heat removal systems are the CCS and the CSS. The CCS fan coolers are designed to operate during both normal plant operations and under loss- of-coolant accident [LOCA] or main steam line break (MSLB) conditions. The CSS is designed to operate during accident conditions only.

   The heat removal capacity of the CCS and CSS is sufficient to keep the containment temperature and pressure below design conditions for any size break, up to and including a double-ended break of the largest reactor coolant pipe. The systems are also designed to mitigate the consequences of any size break, up to and including a double-ended break of a main stream line. The CCS and CSS continue to reduce containment pressure and temperature and maintain them at acceptable levels post-accident.

   The CCS and CSS at [PLANT NAME] each consist of [Substitute plant- specific configuration if it differs from the following description] two redundant loops and are designed such that a single failure does not degrade their ability to provide the required heat removal capability. Two of four containment fan coolers and one CSS loop are powered from one safety-related bus. The other two containment fan coolers and CSS loop are powered from another independent safety- related bus. The loss of one bus does not affect the ability of the containment heat removal systems to maintain containment temperature and pressure below the design values in a post-accident mode.

   The [PLANT NAME] CSS consists of [Substitute plant-specific configuration if it differs from the following description] two independent and redundant loops each containing a spray pump, shutdown heat exchanger, piping, valves, spray headers, and spray nozzles. It has two modes of operation, which are:

1. The injection mode, during which the system sprays borated water from the refueling water tank (RWT) into the containment, and

2. The recirculation mode, which is automatically initiated by the recirculation actuation signal (RAS) after low level is reached in the RWT. During this mode of operation, the safety injection system (SIS) sump provides suction for the spray pumps.

   Containment spray is automatically initiated by the containment spray actuation signal coincident with the safety injection actuation signal and high containment pressure signal. If required, the operator can manually activate the system from the main control room.

   Each CSS pump, together with a CCS loop, provides the flow necessary to remove the heat generated inside the containment following a LOCA or MSLB. Upon system activation, the pumps are started and the borated water flows into the containment spray headers. When low level is reached in the RWT, sufficient water has been transferred to the containment to allow for the recirculation mode of operation. Spray pump suction is automatically realigned to the SIS sump upon a RAS.

   During the recirculation mode, the spray water is cooled by the shutdown heat exchangers prior to discharge into the containment. The shutdown heat exchangers are cooled by the component cooling water system. Post-LOCA pH control is provided by [Substitute plant-specific configuration if it differs from the following description] trisodium phosphate dodecahydrate, which is stored in stainless steel baskets located in the containment near the SIS sump intake.

   The longer CT for an inoperable CSS train will enhance overall plant safety by avoiding potential unscheduled plant

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   shutdowns and allowing greater availability of safety significant components during shutdown. In addition, this extension provides for increased flexibility in scheduling and performing maintenance and surveillance activities in order to enhance plant safety and operational flexibility during lower modes of operation.

   4.0 Technical analysis

   [LICENSEE] has reviewed References 1 and 2, as well as TSTF-409, Rev. 2, and the model SE published on [DATE] ([] FR []) as part of the CLIIP Notice of Availability. [LICENSEE] has applied the methodology in Reference 1 to develop the proposed TS changes. [LICENSEE] has also concluded that the justifications presented in TSTF-409, Rev. 2 and the model SE prepared by the NRC staff are applicable to [PLANT NAME], and justify this amendment for the incorporation of changes to the [PLANT NAME] TS.

   In determining the suitability and safety impact of its adoption of TSTF-409, Rev. 2, [LICENSEE] analyzed the effect of increasing the CT for one CSS train to remain out of service using both traditional engineering considerations and probabilistic risk assessment (PRA) methods.

   4.1 Traditional (Deterministic) Engineering Analysis

   The functions and operation of the CSS and CCS were described in Section 3.0 of this application. Based on a review of the design-basis requirements for the CSS, [LICENSEE] concluded that the loss of one CSS train is well within the design-basis analyses. This conclusion is based on the fact that each CSS pump, together with a CCS loop, provides the flow necessary to remove the heat generated inside the containment following a LOCA or MSLB. Therefore, the combination of one CSS pump and one CCS loop can carry out the design functions of maintaining the containment pressure and temperature at acceptably low levels following a design-basis accident (DBA), and limiting offsite radiation levels by reducing the pressure differential between the containment atmosphere and the external environment, thereby decreasing the driving force for fission product leakage across the containment.

   The plant status with one CSS train and one CCS train inoperable is covered by TS 3.6.6A, ACTION [D], which states:

   ``[With] one containment spray and one containment cooling train inoperable, restore containment spray train to OPERABLE status within 72 hours, or restore containment cooling train to OPERABLE status within 72 hours.''

   ACTION [D] ensures that the iodine removal capabilities of the CSS are available, along with 100 percent of the heat removal needs after an accident. The supporting analyses performed in Reference 1 did not evaluate the concurrent inoperabilities of one CSS train and one CCS train, therefore, the current CT of 72 hours is retained in Condition

   [D] . The 72 hour Completion Time was developed taking into account the redundant heat removal capabilities afforded by combinations of the CSS and CCS, the iodine removal function of the CSS, and the low probability of a DBA occurring during this period.

   4.2 Probabilistic Risk Assessment Evaluation

   [LICENSEE] evaluated the proposed CT extension for the CSS using Reference 3 and Reference 4. This is the same methodology that the NRC staff used in Reference 2. The Key Principles of A Risk-Informed Integrated Decisionmaking Process listed in Reference 3 are as follows:

   Principle I: The proposed change meets the current regulations. Principle II: The proposed change is consistent with the defense-in- depth philosophy. Principle III: The proposed change maintains sufficient safety margin. Principle IV: When the proposed change results in an increase in core damage frequency or risk, the increase should be small and consistent with the Commission's Safety Goal Policy Statement. Principle V: The impact of the proposed change should be monitored using performance measurement strategies.

   In Reference 2, the NRC staff found, and [LICENSEE] agrees, that in risk-informed TS CT applications, Principle I is met, since regulations do not require specific CTs, but, rather, require ``remedial actions'' when an LCO cannot be met. Additionally, in its analysis of Principle III, the NRC staff found, and [LICENSEE] agrees, that the proposed CT extension maintains sufficient safety margins, For [PLANT NAME], the loss of one CSS train is well within the plant's design basis.

   In Reference 2, the NRC staff determined that the intent of Principles II, IV, and V would be met by a three-tiered approach to evaluate the plant-specific risk impact associated with the proposed TS changes, consistent with the requirements of Reference 4. The first tier evaluates the plant-specific PRA model and the impact of the proposed CT extension on plant operational risk. The second tier addresses the need to preclude potentially high risk configurations by identifying the need for any additional constraints or compensatory actions that, if implemented, would avoid or reduce the probability of a risk-significant configuration during the time when one CSS train is out of service. The third tier evaluates [LICENSEE'S] proposed Configuration Risk Management Program (CRMP) to ensure that the applicable plant configuration will be appropriately assessed from a risk perspective before entering into or during the proposed CT.

   In addition, the NRC staff determined in Reference 2, that the risk analysis methodology and approach used by the CEOG to estimate the risk impact of increasing the CT were reasonable. For most plants that participated in the joint application report, the NRC staff found that the risk impact was shown to be consistent with the acceptance guidelines for change in core damage frequency ([Delta]CDF), change in large early release frequency ([Delta]LERF), incremental conditional core damage probability (ICCDP), and incremental conditional large early release probability (ICLERP) specified in References 3 and 4 and Chapters 19.0 and 16.1 of Reference 5. However, not all Combustion Engineering (CE) plants participated in the joint application report, and the estimated risk impacts for some plans exceeded the Reference 3 and/or Reference 4 acceptance guidelines, which would require additional justifications and/or compensatory measures to be provided for these plants to be determined to have acceptable risk impacts.

   In addition, the NRC staff found that the Tier 2 and Tier 3 evaluations, as described in Reference 4, could not be approved generically since they were not complete, which would require that each individual plant-specific license amendment seeking adoption of TSTF- 409, Rev. 2 would need to include an assessment with respect to the Tier 2 and Tier 3 principles of Reference 4. 4.2.1 Conditions and Supporting Information

   The following conditions are provided to support adoption of TSTF- 409, Rev. 2 by [PLANT NAME]. Responses to the conditions are contained in Attachments 1 through 8 to this application: [NOTE: Licensees who cannot meet the Expectation and Acceptance Criteria listed in these conditions, or choose not to submit the associated information, should not

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   submit an application to adopt TSTF-409, Rev. 2 under the CLIIP.]

1. As shown in Attachment 1, the plant-specific Tier 1 information associated with extending the CSS CT meets the acceptance guidelines of References 3 and 4 associated with [Delta]CDF, [Delta]LERF, ICCDP, and ICLERP.

   [EXPECTATIONS/ACCEPTANCE CRITERIA: the licensee's submittal must provide the [Delta]CDF, [Delta]LERF, ICCDP, and ICLERP values related to the CSS 7-day CT and confirm that these values meet the associated acceptance guidelines of References 3 and 4 as no more than a small risk increase (i.e., are in Region II or III of the acceptance guidelines figures). The licensee should utilize an ``average maintenance'' PRA model for this assessment. If the licensee utilizes a ``zero maintenance'' PRA model for the assessment, they should state they are using a ``zero maintenance'' model in the evaluation, and provide a discussion as to the ability of that model to produce comparable results to the ``average maintenance'' assessment.]

2. As shown in Attachment 2, the technical adequacy (quality) of

   [PLANT NAME'S] plant-specific PRA is acceptable for this application in accordance with the guidance provided in Reference 3. Specifically, the supporting information addresses the following areas:

   1. Justification that the plant-specific PRA reflects the as-built, as-operated plant.

   2. Discussion of plant-specific PRA updates and upgrades since the individual plant examination (IPE), individual plant examination of external events (IPEEE), and subsequent peer reviews and self- assessment. Reference to past submittals discussing this information is acceptable.

   3. Discussion of plant-specific PRA peer reviews and/or self- assessments performed, their overall conclusions, any facts and observations (F&Os) applicable to this application, and the licensee evaluation and resolution (e.g., by implementing model changes and/or sensitivity studies) of these F&Os to demonstrate the conclusions of the plant-specific analyses for this application are not adversely impacted (i.e., continued acceptability of the proposed extension of the CSS CT).

   4. Description of the licensee's plant-specific PRA configuration control (quality assurance) program and associated procedures.

   5. Overall determination of the adequacy of the plant-specific PRA with respect to this application.

      [EXPECTATION: The licensee's submittal must describe the scope of the plant-specific PRA and must justify its technical adequacy (quality) for this application in accordance with the guidance provided in Reference 3. Specifically, the supporting information must address each area in sufficient detail as shown in the following ACCEPTANCE CRITERIA:

   1. The licensee must provide a justification that confirms that the plant-specific PRA reflects the as-built, as-operated plant. This should include a description of the licensee's data and model update process, and the frequency of these activities. The licensee should also describe how the plant/corporate PRA staff are involved in (and/or made aware of) plant and operational/procedural modifications.

   2. The licensee must provide a summary description of the plant- specific PRA updates and upgrades since the IPE and peer review of their plant and confirm that the changes identified during the IPEEE have been implemented or otherwise dispositioned.

   3. The licensee must discuss their plant-specific PRA peer reviews and/or any self-assessments performed (especially noting those conducted per the Nuclear Energy Institute (NEI) industry peer review guidelines and American Society of Mechanical Engineers (ASME) PRA Standard), their overall conclusions, any A&B level F&Os applicable to this application, and the licensee's evaluation and resolution (e.g., by implementing model changes and/or sensitivity studies) of these A&B level F&Os to demonstrate the conclusions of the plant-specific analyses for this application are not adversely impacted (i.e., continued acceptability of the proposed extension of the CSS CT).

   4. The licensee must describe their plant-specific PRA configuration control (quality assurance) program and associated procedures.

   5. The licensee must make an overall determination of the adequacy of their plant-specific PRA, confirming it is adequate with respect to this application.]

3. Attachment 3 provides supporting information verifying that the plant risk impact associated with external events (e.g., fires, seismic, tornados, high winds, etc.) does not adversely impact or has no impact on the conclusions of the plant-specific analyses for this application and that the overall combined plant CDF and LERF are expected to be within the acceptance guidelines as identified in References 3 and Reference 4 (i.e., total CDF