ML072490045
| ML072490045 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 12/06/2007 |
| From: | Bhalchandra Vaidya NRC/NRR/ADRO/DORL/LPLIV |
| To: | Venable J Entergy Operations |
| Vaidya B, NRR/DORL/LPL4, 415-3308 | |
| Shared Package | |
| ML072490028 | List: |
| References | |
| TAC MD6016 | |
| Download: ML072490045 (30) | |
Text
December 6, 2007 Mr. Joseph E. Venable Site Vice President Entergy Operations, Inc.
River Bend Station 5485 US Highway 61N St. Francisville, LA 70775
SUBJECT:
RIVER BEND STATION, UNIT 1 - ISSUANCE OF AMENDMENT RE:
TECHNICAL SPECIFICATIONS CHANGE REGARDING MODE CHANGE LIMITATIONS (TSTF-359) USING THE CONSOLIDATED LINE ITEM IMPROVEMENT PROCESS, AND CORRECT EXAMPLE 1.4-1 (TSTF-485)
Dear Mr. Venable:
The Nuclear Regulatory Commission (NRC) has issued the enclosed Amendment No. 156 to Facility Operating License No. NPF-47 for the River Bend Station, Unit 1 (RBS). This amendment consists of changes to the Technical Specifications (TSs) in response to your application dated July 2, 2007, under the NRC's Consolidated Line Item Improvement Process.
The amendment modified the RBS TS requirements for MODE change limitations in Limiting Condition for Operation 3.0.4 and Surveillance Requirement 3.0.4. The TS changes are consistent with Revision 9 of NRC-approved Industry TS Task Force (TSTF) Standard TS Change Traveler, TSTF-359, Increase Flexibility in MODE Restraints. In addition, consistent with NRC-approved TSTF-485, Revision 0, "Correct Example 1.4-1," the amendment also changed TS Section 1.4, Frequency, Example 1.4-1, Surveillance Requirements, to accurately reflect the changes made by TSTF-359.
A copy of our related Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.
Sincerely,
/RA/
Bhalchandra Vaidya, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-458
Enclosures:
- 1. Amendment No. 156 to NPF-47
- 2. Safety Evaluation cc w/encls: See next page
PKG ML072490028, Amendment/License ML072490045, TS Pages ML072490052
(*) No substantial changes to SE Input
(**) Not Required per SE Input Memo from ITSB
(***) See previous concurrence OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/ITSB/BC(*)
OGC(**)
NRR/LPL4/BC NAME BVaidya JBurkhardt (***)
TKobetz Not Required THiltz (***)
DATE 10/15/07 10/15/07 9/13/07 9/13/07 11/30/07
September 2007 River Bend Station cc:
Senior Vice President Entergy Nuclear Operations P.O. Box 31995 Jackson, MS 39286-1995 Senior Vice President and COO Entergy Operations, Inc.
P.O. Box 31995 Jackson, MS 39286-1995 Vice President, Operations Support Entergy Operations, Inc.
P.O. Box 31995 Jackson, MS 39286-1995 General Manager, Plant Operations Entergy Operations, Inc.
River Bend Station 5485 US Highway 61N St. Francisville, LA 70775 Director, Nuclear Safety & Licensing Entergy Services, Inc.
440 Hamilton Avenue White Plains, NY 10601 Director, Nuclear Safety Assurance Entergy Operations, Inc.
River Bend Station 5485 US Highway 61N St. Francisville, LA 70775 Senior Manager, Nuclear Safety & Licensing Entergy Services, Inc.
P.O. Box 31995 Jackson, MS 39286-1995 Manager, Licensing Entergy Operations, Inc.
River Bend Station 5485 US Highway 61N St. Francisville, LA 70775 Louisiana Department of Environmental Quality Radiological Emergency Planning and Response Division P.O. Box 4312 Baton Rouge, LA 70821-4312 Louisiana Department of Environmental Quality Office of Environmental Compliance P.O. Box 4312 Baton Rouge, LA 70821-4312 Attorney General State of Louisiana P.O. Box 94095 Baton Rouge, LA 70804-9095 President of West Feliciana Police Jury P.O. Box 1921 St. Francisville, LA 70775 Brian Almon Public Utility Commission William B. Travis Building P.O. Box 13326 1701 North Congress Avenue Austin, Texas 78701-3326 Mr. Jim Calloway Public Utility Commission of Texas 1701 N. Congress Avenue Austin, TX 78711-3326 Ms. H. Anne Plettinger 3456 Villa Rose Drive Baton Rouge, LA 70806 Richard Penrod, Senior Environmental Scientist/State Liaison Officer Office of Environmental Services Northwestern State University Russell Hall, Room 201 Natchitoches, LA 71497 Senior Resident Inspector P.O. Box 1050 St. Francisville, LA 70775 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064
ENTERGY GULF STATES, INC. **
AND ENTERGY OPERATIONS, INC.
DOCKET NO. 50-458 RIVER BEND STATION, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 156 License No. NPF-47 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Entergy Gulf States, Inc.* (the licensee) dated July 2, 2007, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, as amended, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D.
The issuance of this license amendment will not be inimical to the common defense and security or to the health and safety of the public; and Entergy Operations, Inc. is authorized to act as agent for Entergy Gulf States, Inc., and has exclusive responsibility and control over the physical construction, operation and maintenance of the facility.
- Entergy Gulf States, Inc., has merged with a wholly owned subsidiary of Entergy Corporation. Entergy Gulf States, Inc., was the surviving company in the merger.
E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and Paragraph 2.C.(2) of Facility Operating License No. NPF-47 is hereby amended to read as follows:
(2)
Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 156 and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. EOI shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
3.
The license amendment is effective as of its date of issuance and shall be implemented within 120 days from the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Thomas G. Hiltz, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Facility Operating License No. NPF-47 and Technical Specifications Date of Issuance: December 6, 2007
ATTACHMENT TO LICENSE AMENDMENT NO. 156 FACILITY OPERATING LICENSE NO. NPF-47 DOCKET NO. 50-458 Replace the following pages of the Facility Operating License No. NPF-47 and Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by Amendment number and contain marginal lines indicating the areas of change.
Facility Operating License Remove Insert 3
3 Technical Specifications Remove Insert 1.0-26 1.0-26 3.0-1 3.0-1 3.0-2 3.0-2 3.0-5 3.0-5 3.3-19 3.3-19 3.3-23 3.3-23 3.4-17 3.4-17 3.4-18 3.4-18 3.4-20 3.4-20 3.4-22 3.4-22 3.5-1 3.5-1 3.5-10 3.5-10 3.6-41 3.6-41 3.6-44 3.6-44 3.8-1 3.8-1 (3)
EOI, pursuant to the Act and 10 CFR Part 70, to receive, possess and to use at any time special nuclear material as reactor fuel, in accordance with the limitations for storage and amounts required for reactor operation, as described in the Final Safety Analysis Report, as supplemented and amended; (4)
EOI, pursuant to the Act and 10 CFR Parts 30, 40 and 70, to receive, possess, and use at any time any byproduct, source and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required; (5)
EOI, pursuant to the Act and 10 CFR Parts 30, 40 and 70, to receive, possess, and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and (6)
EOI, pursuant to the Act and 10 CFR Parts 30, 40 and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility.
C.
This license shall be deemed to contain and is subject to the conditions specified in the Commission's regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:
(1)
Maximum Power Level EOI is authorized to operate the facility at reactor core power levels not in excess of 3091 megawatts thermal (100% rated power) in accordance with the conditions specified herein. The items identified in Attachment 1 to this license shall be completed as specified. Attachment 1 is hereby incorporated into this license.
(2)
Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 156 and the l
Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. EOI shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
Amendment No. 156
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 156 TO FACILITY OPERATING LICENSE NO. NPF-47 ENTERGY OPERATIONS, INC.
RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458
1.0 INTRODUCTION
By application dated July 2, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML071910352), Entergy Operations, Inc., et al. (EOI, Entergy, or the licensee), requested changes to the Technical Specifications (TSs) for River Bend Station, Unit 1 (RBS).
The proposed amendment would modify RBS TS requirements for MODE change limitations in Limiting Condition for Operation (LCO) 3.0.4 and Surveillance Requirement (SR) 3.0.4. The proposed TS changes are consistent with Revision 9 of U.S. Nuclear Regulatory Commission (NRC)-approved Industry TS Task Force (TSTF) Standard TS (STS) Change Traveler, TSTF-359, Increase Flexibility in MODE Restraints. The availability of TSTF-359 for adoption by licensees was announced in the Federal Register on April 4, 2003 (68 FR 16579), using the Consolidated Line Item Improvement Process (CLIIP).
In addition, the proposed amendment would also change TS Section 1.4, Frequency, Example 1.4-1, Surveillance Requirements, to accurately reflect the changes made to LCO 3.0.4. This change is consistent with TSTF-485, Revision 0, "Correct Example 1.4-1,"
which was approved by NRC letter dated December 6, 2005 (ADAMS Accession No. ML053460302), and has been incorporated into the STS, Revision 3.1. Also, consistent with changes to LCO 3.0.4 and SR 3.0.4, the licensee proposed changes in various other relevant TS sections, as summarized in Table 1 in Section 1.2 of this Safety Evaluation (SE).
1.1 Optional Changes and Variations The licensee's application for the amendment to the facility operating license (FOL) requests TS changes described in TSTF-359, Revision 9, and the NRC staff's model SE published on April 4, 2003, including the following variations:
1.
Due to differences between the RBS TS and TS Bases and their corresponding model [Boiling-Water Reactor] BWR/6 STS (NUREG-1434), in some cases, variances from the TSTF marked-up changes are made. These variances are discussed below and do not affect the adoption or application of TSTF-359, Revision 9.
a.
RBS TS LCO 3.4.7 RCS Leakage Detection Instrumentation, differs from the BWR/6 STS. The BWR/6 STS applies the "LCO 3.0.4 is not applicable" NOTE to all ACTIONS. In RBS TS 3.4.7, RCS Leakage Detection Instrumentation, the NOTE is applied to REQUIRED ACTIONS A and D only. EOI has provided mark-ups which delete the NOTE in each location.
b.
In the TSTF mark-ups, BWR/6 STS 3.6.3.1, Primary Containment Hydrogen Recombiners, the NOTE "LCO 3.0.4 is not applicable," was removed from REQUIRED ACTION A. The RBS equivalent TS was deleted per TS Amendment 142, issued in NRC letter dated October 4, 2004. Therefore, RBS TS 3.6.3.1 markups are not included in this package.
2.
TS Section 1.4 Frequency Section 1.4, Frequency, Example 1.4-1, is revised to be consistent with the changes to SR 3.0.4. SR 3.0.4 was revised by TSTF-359, Revision 9, and the current example is not consistent with the Technical Specification requirements.
The second paragraph of Example 1.4-1 is revised to reflect the changes made to SR 3.0.4.
1.2 Changes to Other TS Sections As a result of the changes to TS LCO 3.0.4 and SR 3.0.4, the notes in the various related TS sections were revised as administrative changes. They are summarized in Table 1 below:
TABLE 1 Item No.
RBS TS No.
RBS TS Title Description of Change 1
1.4 Frequency The second paragraph of Example 1.4-1 is revised to reflect the changes made to SR 3.0.4.
2 LCO 3.0.4 No Title Existing LCO has been replaced in its entirety with the revised wording.
3 SR 3.0.4 No Title Existing SR has been replaced in its entirety with the revised wording.
4 3.3.3.1 Post Accident Monitoring (PAM)
Instrumentation The ACTIONS NOTE stating LCO 3.0.4 is not applicable has been deleted and the remaining NOTE renumbered.
5 3.3.3.2 Remote Shutdown System The ACTIONS NOTE stating LCO 3.0.4 is not applicable has been deleted and the remaining NOTE renumbered.
Item No.
RBS TS No.
RBS TS Title Description of Change 6
3.4.7 RCS [Reactor Coolant System]
Leakage Detection Instrumentation The NOTE in both REQUIRED ACTIONS A and D, stating LCO 3.0.4 is not applicable have been deleted.
7 3.4.8 RCS Specific Activity The existing NOTE for REQUIRED ACTIONS is replaced with a NOTE stating LCO 3.0.4.c is applicable.
8 3.4.9 Residual Heat Removal (RHR)
Shutdown Cooling System - Hot Shutdown The ACTIONS NOTE stating LCO 3.0.4 is not applicable has been deleted and the remaining NOTE renumbered.
9 3.5.1 ECCS [Emergency Core Cooling Systems] - Operating A NOTE is added to the ACTIONS stating LCO 3.0.4.b is not applicable to HPCS.
10 3.5.3 RCIC [Reactor Core Isolation Cooling] System - Shutdown A NOTE is added to the ACTIONS stating LCO 3.0.4.b is not applicable to RCIC.
11 3.6.3.1 Deleted by Amendment No. 142, dated October 4, 2004.
Not applicable.
12 3.6.3.2 Primary Containment and Drywell Hydrogen Igniters The REQUIRED ACTION A.1 NOTE stating LCO 3.0.4 is not applicable has been deleted.
13 3.6.3.3 Primary Containment/Drywell Hydrogen Mixing System The REQUIRED ACTION A.1 NOTE stating LCO 3.0.4 is not applicable. has been deleted.
14 3.8.1 AC [Alternating Current] Sources -
Operating A NOTE is added to the ACTIONS stating LCO 3.0.4.b is not applicable to DGs [Diesel Generators].
1.3 Verification and Commitments As discussed in the notice of availability, Applicability section, published in the Federal Register on April 4, 2003 (68 FR 16579), for this TS improvement, the RBS TS has incorporated the TS Bases Control Program (TS 5.5.11) and has adopted the requirements of SR 3.0.1 and associated bases in its TS.
Further, the licensee, in its submission, stated that, as discussed in the notice of availability, Applicability section, published in the Federal Register on April 4, 2003 (68 FR 16579), for this TS improvement, the plant-specific verifications were performed as follows:
EOI has proposed changes to the TS Bases for LCO 3.0.4 and SR 3.0.4 which state that use of the TS mode change limitation flexibility established by LCO 3.0.4 and SR 3.0.4 is not to be interpreted as endorsing the failure to exercise the good practice of restoring systems or components to operable status before entering an associated MODE or other specified condition in the TS Applicability.
The proposed changes to the [TS] Bases for LCO 3.0.4 and SR 3.0.4 provide details on how to implement the new requirements. The Bases changes provide guidance for changing Modes or other specified conditions in the Applicability when an LCO is not met. The Bases changes describe in detail how:
LCO 3.0.4.a allows entry into a MODE or other specified condition in the Applicability with the LCO not met when the associated ACTIONS to be entered permit continued operation in the MODE or other specified condition in the Applicability for an unlimited period of time; LCO 3.0.4.b allows entry into a MODE or other specified condition in the Applicability with the LCO not met after performance of a risk assessment addressing inoperable systems and components, consideration of the results, determination of the acceptability of entering the MODE or other specified condition in the Applicability, and establishment of risk management actions, if appropriate; and LCO 3.0.4.c allows entry into a MODE or other specified condition in the Applicability with the LCO not met based on a Note in the Specification, which is typically applied to Specifications which describe values and parameters (e.g., RCS Specific Activity) though it may be applied to other Specifications based on NRC plant-specific approval. The Bases also state that any risk impact should be managed through the program in place to implement 10 CFR 50.65(a)(4)
[paragraph 50.65(a)(4) of Title 10 of the Code of Federal Regulations (10 CFR)]
and its implementation guidance, NRC Regulatory Guide 1.182, Assessing and Managing Risk Before Maintenance Activities at Nuclear Power Plants, and that the results of the risk assessment shall be considered in determining the acceptability of entering the MODE or other specified condition in the Applicability, and any corresponding risk management actions. Upon entry into a MODE or other specified condition in the Applicability with the LCO not met, LCO 3.0.1 and LCO 3.0.2 require entry into the applicable Conditions and Required Actions until the Condition is resolved, until the LCO is met, or until the unit is not within the Applicability of the Technical Specification. The Bases also state that SR 3.0.4 does not restrict changing MODES or other specified conditions of the Applicability when a Surveillance has not been performed within the specified Frequency, provided the requirement to declare the LCO not met has been delayed in accordance with SR 3.0.3. Finally, as noted in Section 1.0 above [of the licensee's July 2, 2007, application], the RBS TS already contain a TS Bases Control Program (TS 5.5.11) and SR 3.0.1, thus these requirements do not need to be added to the TS.
1.4 Background
On July 17, 2002, the Nuclear Energy Institute (NEI) Risk-Informed Technical Specifications Task Force (RITSTF) submitted proposed change, TSTF-359, Revision 7, to the STS (NUREGs 1430-1434) on behalf of the industry. TSTF-359, Revision 7, is a proposal to change the STS LCO 3.0.4 and SR 3.0.4 requirements regarding mode change limitations by risk-informing limitations on entering the mode of applicability of an LCO. The Notice of Opportunity to Comment on the model SE using the CLIIP with respect to this change was published in the Federal Register on August 2, 2002 (67 FR 50475). The NRC staff prepared a model SE incorporating changes resulting from public comments. The NRC staff has since made minor editorial changes to the SE. TSTF-359, Revision 8, as modified, provides the complete approved change as discussed in the Federal Register notice dated April 4, 2003. The RITSTF (1)
MODE numbers decrease in the transition "up to a higher mode of operation"; power operation is MODE 1.
subsequently incorporated the modifications identified in the April 4, 2003, notice into TSTF-359, Revision 9.
This proposal is one of the industrys initiatives under the risk-informed TS program. These initiatives are intended to maintain or improve safety while reducing unnecessary burden and to make TS requirements consistent with the Commissions other risk-informed regulatory requirements, in particular, 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants, or the Maintenance Rule. The current RBS TS LCO 3.0.4 specifies that the plant cannot go to higher modes of operation(1) (i.e., move towards power operation) except when the associated ACTIONS to be entered permit continued operation in the MODE or other specified condition in the Applicability for an unlimited period of time. In addition, RBS TS SR 3.0.4 restricts mode changes unless the LCOs Surveillances have been met within their specified surveillance Frequency.
The industry believes that this requirement is unnecessarily restrictive and can unduly delay plant startup while considerable resources are being used to resolve startup issues that are risk insignificant or low risk. A maintenance activity that takes longer than planned can delay a mode change and adversely impact a utilitys orderly plant startup and return to power operation. In Revision 3.1 of NUREG-1434, Standard Technical Specifications for General Electric BWR/6, dated December 1, 2005, LCO 3.0.4 and SR 3.0.4 were revised to allow entry into a mode without meeting its LCO after performance of a risk assessment addressing inoperable systems and components, and establishment of appropriate risk management actions. The licensee proposes to adopt the provisions of LCO 3.0.4 and SR 3.0.4 in NUREG-1434, STS, Revision 3.1. The objective of the proposed change is to provide additional operational flexibility without compromising plant safety.
The proposed changes to LCO 3.0.4 and SR 3.0.4 would allow, for systems and components, mode changes into a TS condition that has a specific required action and completion time (CT).
The licensee will utilize the LCO 3.0.4 and SR 3.0.4 allowances only when they determine that there is a high likelihood that the LCO will be satisfied within the LCO CT after the mode change. In addition, the LCO 3.0.4 and SR 3.0.4 allowances can be applied to values and parameters in specifications when explicitly stated in the TSs (non-system/component TSs such as RCS Specific Activity). These changes are in addition to the current mode change allowance when a required action has an indefinite CT. The LCO 3.0.4 and SR 3.0.4 mode change allowances are not permitted for the systems and components, termed higher risk listed in Section 3.1.2, Identification of Risk-Important TS Systems and Components, for the modes specified. Two examples are: (1) BWR plants cannot transition up into any mode with an inoperable DG (including other emergency/shutdown AC power supplies); and (2) BWR plants cannot transition from Mode 5 to Mode 4 without required RHR system loops operable.
2.0 REGULATORY EVALUATION
In 10 CFR 50.36, Technical specifications, the Commission established its regulatory requirements related to the content of TSs. Pursuant to 10 CFR 50.36, TSs are required to include items in the following five specific categories related to station operation: (1) safety limits, limiting safety system settings, and limiting control settings, (2) LCOs, (3) SRs, (4) design features, and (5) administrative controls. The rule does not specify the particular requirements to be included in a plants TSs. As stated in 10 CFR 50.36(c)(2)(i), the Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications.... By convention, the LCOs and related SRs are contained in Sections 3.1 through 3.10 of the STSs. STS Section 3.0, on LCO and SR Applicability, provides details or ground rules for complying with the LCOs and related SRs. STS LCO 3.0.4 and SR 3.0.4 address requirements for LCO compliance when transitioning between modes of operation.
TSs have taken advantage of risk technology as experience and capability have increased.
Since the mid-1980s, the NRC has been reviewing and granting improvements to the TSs that are based, at least in part, on probabilistic risk assessment (PRA) insights. In its final policy statement on TS improvements of July 22, 1993, the Commission stated that it expects that licensees will utilize any plant-specific PRA or risk survey in preparing their TS-related submittals. In evaluating these submittals, the NRC staff applies the guidance in Regulatory Guide (RG) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, dated November 2002, and in RG 1.177, An Approach for Plant-Specific, Risk-Informed Decision-making: Technical Specifications, dated August 1998. The NRC staff has appropriately adapted this guidance to assess the acceptability of upward mode changes with equipment inoperable. This review had the following objectives:
To ensure that the plant risk does not increase unacceptably during the actual implementation of the proposed change (e.g., when the plant enters a higher mode while an LCO is not met). This risk increase is referred to as temporary.
To compare and assess the risk impact of the proposed change to the acceptance guidelines of the Commissions Safety Goal Policy Statement, as documented in RG 1.174. The risk impact, which is measured by the average yearly risk increase associated with the change, aims at minimizing the cumulative risk associated with the proposed change so that the plants average baseline risk is maintained within a minimal range.
To assess the licensees ability to identify risk-significant configurations resulting from maintenance or other operational activities and take appropriate compensatory measures to avoid such configurations.
The NRC staff reviewed the reliance on 10 CFR 50.65(a)(4) for the non-higher-risk systems and components, and related guidance to assess and manage the risk of upward mode changes. The Commission has found that compliance with the industry guidance for implementation of 10 CFR 50.65(a)(4), as endorsed by RG 1.182, Assessing and Managing Risk before Maintenance Activities at Nuclear Power Plants, and mandated by STS LCO 3.0.4, SR 3.0.4, and SR 3.0.3, satisfies the configuration risk management objectives of RG 1.177 for TS surveillance interval and CT extensions. Reliance on 10 CFR 50.65(a)(4) processes that are consistent with the provisions of the NRC-endorsed industry guidance was also found adequate for managing risk of missed surveillances as described in the Federal Register on September 28, 2001 (66 FR 49714).
The NRC staff review also had the objective of ensuring that existing inspection programs have the necessary controls in place to allow NRC staff to oversee the implementation of the proposed change and reliance on 10 CFR 50.65(a)(4) processes or programs. The inspection program also allows the NRC staff to adequately assess the licensees performance associated with risk assessments. The review encompassed inspection procedures (IPs) (i.e., NRC IP 62709, dated December 28, 2000, Configuration Risk Assessment and Risk Management Process, and NRC IP 71111.13, dated January 17, 2002, Maintenance Risk Assessments and Emergent Work Control), the significance determination process (SDP) (i.e., Inspection Manual Chapter (IMC) 0609, Appendix K, dated May 19, 2005, Maintenance Risk Assessment and Risk Management Significance Determination Process), enforcement guidance (i.e., draft Enforcement Manual Section 8.1.11, Actions Involving the Maintenance Rule), and the associated reactor oversight process (ROP).
2.1 Proposed Change to LCO 3.0.4 and SR 3.0.4 Currently, LCO 3.0.4 does not allow entrance into a higher mode (or other specified condition) in the applicability when an LCO is not met, except when the associated actions to be entered permit continued operation in that mode or condition indefinitely or a specific exception is granted. Similarly, when an LCOs surveillances have not been met within their specified frequency, entry into a higher mode (or other specified condition) is not allowed by SR 3.0.4.
The current RBS TS LCO 3.0.4 reads:
When an LCO is not met, entry into a MODE or other specified condition in the Applicability shall not be made except when the associated ACTIONS to be entered permit continued operation in the MODE or other specified condition in the Applicability for an unlimited period of time. This Specification shall not prevent changes in MODES or other specified conditions in the Applicability that are required to comply with ACTIONS or that are part of a shutdown of the unit.
Exceptions to this Specification are stated in the individual Specifications. These exceptions allow entry into MODES or other specified conditions in the Applicability when the associated ACTIONS to be entered allow unit operation in the MODE or other specified condition in the Applicability only for a limited period of time.
LCO 3.0.4 is only applicable for entry into a MODE or other specified condition in the Applicability in MODES 1, 2, and 3.
The revised LCO 3.0.4 will read:
When an LCO is not met, entry into a MODE or other specified condition in the Applicability shall only be made:
a.
When the associated ACTIONS to be entered permit continued operation in the MODE or other specified condition in the Applicability for an unlimited period of time, b.
After performance of a risk assessment addressing inoperable systems and components, consideration of the results, determination of the acceptability of entering the MODE or other specified condition in the Applicability, and establishment of risk management actions, if appropriate; exceptions to this Specification are stated in the individual Specifications, or c.
When an allowance is stated in the individual value, parameter, or other Specification.
This Specification shall not prevent changes in MODES or other specified conditions in the Applicability that are required to comply with ACTIONS or that are part of a shutdown of the unit.
The current RBS TS SR 3.0.4 reads:
Entry into a MODE or other specified condition in the Applicability of an LCO shall not be made unless the LCO's Surveillances have been met within their specified Frequency.
This provision shall not prevent entry into MODES or other specified conditions in the Applicability that are required to comply with ACTIONS or that are part of a shutdown of the unit.
SR 3.0.4 is only applicable for entry into a MODE or other specified condition in the Applicability in MODES 1, 2, and 3.
The revised SR 3.0.4 will conform to the changes to LCO 3.0.4 and read:
Entry into a MODE or other specified condition in the Applicability of an LCO shall only be made when the LCO's Surveillances have been met within their specified Frequency, except as provided by SR 3.0.3. When an LCO is not met due to Surveillances not having been met, entry into a MODE or other specified condition in the Applicability shall only be made in accordance with LCO 3.0.4.
This provision shall not prevent entry into MODES or other specified conditions in the Applicability that are required to comply with ACTIONS or that are part of a shutdown of the unit.
The proposed LCO 3.0.4.a retains the current allowance for when the required actions allow indefinite operation. The proposed LCO 3.0.4.b allows entering modes or other specified conditions in the applicability except when higher-risk systems and components (listed in Section 3.1.1), for the mode being entered, are inoperable. The decision for entering a higher mode or condition in the applicability of the LCO will be made by plant management after the required risk assessment has been performed and requisite risk management actions established, through the program established to implement 10 CFR 50.65(a)(4). Entry into the modes or other specified conditions in the applicability of the TS shall be for no more than the duration of the applicable required actions CT, or until the LCO is met. Current notes in individual specifications that permitted mode changes are now encompassed by LCO 3.0.4.b and can be removed. Notes that prohibit mode changes under LCO 3.0.4.b must be added (i.e., for higher-risk systems and components).
The proposed LCO 3.0.4.b allowance can involve multiple components in a single LCO or in multiple LCOs; however, use of the LCO 3.0.4.b provisions are always contingent upon completion of a 10 CFR 50.65(a)(4)-based risk assessment.
The notes limiting the applicability of LCO 3.0.4 and SR 3.0.4 are no longer needed and are removed by TSTF-359, Revision 8. Adding notes to various TS, as defined by the tables of higher-risk systems, precluding entry into Modes 4 and 5 for BWRs is unnecessary by action statements that require immediate CTs, which means that entry into the Mode or other specified condition in the Applicability is not allowed and the notes would be superfluous.
LCO 3.0.4 allowances related to values and parameters of TS are not typically addressed by LCO 3.0.4.b risk assessments, and are, therefore, addressed by a new LCO 3.0.4.c.
LCO 3.0.4.c refers to allowances already in the TS and annotated in the individual TS.
LCO 3.0.4.c also allows for entry into the modes or other specified conditions in the applicability of a TS for no more than the duration of the applicable required actions CT or until the LCO is met or the unit is not within the Applicability of the TS.
2.2 Proposed Change to TS 1.4, Example 1.4-1, Frequency The first paragraph of the current TS 1.4, Example 1.4-1, states:
If the interval as specified by SR 3.0.2 is exceeded while the unit is not in a MODE or other specified condition in the Applicability of the LCO for which performance of the SR is required, the Surveillance must be performed within the Frequency requirements of SR 3.0.2 prior to entry into the MODE or other specified condition. Failure to do so would result in a violation of SR 3.0.4.
The proposed changes to the Example 1.4-1 conform to the changes in TSTF-485, Revision 0, that was approved by the staff on December 6, 2005 (ADAMS Accession No. ML053460302).
The revised Example 1.4-1 would state:
If the interval as specified by SR 3.0.2 is exceeded while the unit is not in a MODE or other specified condition in the Applicability of the LCO for which performance of the SR is required, then SR 3.0.4 becomes applicable. The Surveillance must be performed within the Frequency requirements of SR 3.0.2, as modified by SR 3.0.3, prior to entry into the MODE or other specified condition, or the LCO is considered not met (in accordance with SR 3.0.1) and LCO 3.0.4 becomes applicable.
This change is being made to correct the Example 1.4-1 to conform to the changes made to LCO 3.0.4.
3.0 TECHNICAL EVALUATION
During the development of the current STS, improvements were made to LCO 3.0.4, such as clarifying its applicability with respect to plant shutdowns, cold shutdown mode, and refueling mode. In addition, during the STS development, almost all the LCOs with CTs greater than or equal to 30 days, and many LCOs with CTs greater than or equal to 7 days, were given individual LCO 3.0.4 exceptions. During some conversions to the STS, individual plants provided acceptable justifications for other LCO 3.0.4 exceptions. All of these specific LCO 3.0.4 exceptions allow entry into a mode or other specified condition in the TS applicability while relying on the TS required actions and associated CTs. The proposed change under evaluation would provide standardization and consistency to the use and application of LCO 3.0.4, both internal to and between each of the specifications and STS NUREGs. This proposed change will also ensure consistency through the utilization of appropriate levels of risk assessment of plant configurations for application of LCO 3.0.4. However, nothing in this SE should be interpreted as encouraging upward mode transition with inoperable equipment.
Good practice should dictate that such transitions should normally be initiated only when all required equipment is operable and that mode transition with inoperable equipment should be the exception rather than the rule.
The current LCO 3.0.4.a allowances are retained in the proposal and do not represent a change in risk from the current situation. The proposed LCO 3.0.4.b allowances apply to systems and components, and require a risk assessment prior to utilization to ensure an acceptable level of safety is maintained. The proposed LCO 3.0.4.c allowances apply to parameters and values which have been previously approved by the NRC in a plants specific TS. In its submission, the licensee has provided in their proposed revisions to TS Bases a discussion and list of each NRC-approved, LCO 3.0.4.c-specific value and parameter allowance and revised the TS Bases of LCO 3.0.4, to explain the new allowances and their utilization.
The NRC staff did a qualitative assessment of the risk impact of the proposed change in LCO 3.0.4.b allowances by evaluating how the licensees implementation of the proposed risk-informed approach is expected to meet the requirements of the applicable RGs. The NRC staff referred to the guidance provided in RG 1.174 and RG 1.177. RG 1.177 provides the NRC staffs recommendations on utilizing risk information to assess the impact of proposed changes to nuclear power plant technical specifications on the risk associated with plant operation.
Although RG 1.177 does not specifically address the type of generic change in this proposal, the NRC staff considered the approach documented in RG 1.177 in evaluating the risk information provided in support of the proposed changes in LCO 3.0.4.
The NRC staffs evaluation of how the implementation of the proposed risk-informed approach, used to justify LCO 3.0.4.b allowances, agrees with the objectives of the guidance outlined in RG 1.177, is discussed in Section 3.1. Oversight of the risk-informed approach associated with the LCO 3.0.4.b allowances is discussed in Section 3.2.
3.1 Evaluation of Risk Management Both the temporary and cumulative risk of the proposed change are adequately limited. The temporary risk is limited by the exclusion of higher-risk systems and components, and CTs limits contained in TS (see discussion in SE Section 3.1.1). The cumulative risk is limited by the temporary risk limitations and by the expected low frequency of the proposed mode changes with inoperable equipment (see discussion in SE Section 3.1.4). Adequate NRC oversight of the licensees ability to use the LCO 3.0.4.b provisions under appropriate circumstances, i.e., to identify risk-significant configurations when entering a higher mode or condition in the applicability of an LCO (Section 3.1.5) is provided by NRC inspection of the licensees implementation of 10 CFR 50.65(a)(4) as applied to the proposed change.
3.1.1 Temporary Risk Increases RG 1.177 proposes the incremental conditional core damage probability (ICCDP) and the incremental conditional large early release probability (ICLERP) as appropriate measures of the increase in probability of core damage and large early release, respectively, during the period of implementation of a proposed TS change. In addition, RG 1.177 stresses the need to preclude potentially high risk configurations introduced by the proposed change. The ICCDP associated with any specified plant condition, such as the condition introduced by entering a higher mode with plant equipment inoperable, is expressed by the following equation:
ICCDP = R d = (R1 - Ro) d (1) where:
R
= the conditional risk increase, in terms of core damage frequency (CDF),
caused by the specified condition d
= the duration of the specified plant condition R1
= the plant CDF with the specified condition permanently present Ro
= the plant CDF without the specified condition The same expression can be used for ICLERP by substituting the measure of risk, i.e., large early release frequency (LERF) for CDF. The magnitude of the ICCDP and ICLERP values associated with plant conditions applicable to LCO 3.0.4.b allowances can be managed by controlling the conditional risk increase, R (in terms of both CDF and LERF) and the duration, d, of such conditions. The following sections discuss how the key elements of the proposed risk-informed approach, used to justify LCO 3.0.4.b allowances, are expected to limit R and d and, thus, prevent any significant temporary risk increases.
3.1.2 Identification of Risk-Important TS Systems and Components A major element that limits the risk of the proposed mode change flexibility is the exclusion of certain systems and associated LCOs for the mode change allowance. Technical specifications allow operation in Mode 1 (power operation) with specified levels of inoperability for specified times. This provides a benchmark of currently acceptable risk against which to measure any incremental risk inherent in the proposed LCO 3.0.4.b. If a system inoperability accrues risk at a higher rate in one or more of the transition modes than it would in Mode 1, then an upward transition into that mode should not be allowed without demonstration of a high degree of experience and sophistication in risk management. However, the risk management process evaluated in Section 3.1.5 is adequate if higher-risk systems/components are excluded from the scope of LCO 3.0.4.b.
The importance of most TS systems in mitigating accidents increases as power increases.
However, some TS systems are relatively more important during lower power and shutdown operations, because:
certain events are peculiar to modes of plant operation other than power operation, certain events are more probable at modes of plant operation other than power operation, some modes of plant operation have less mitigation system capability than power operation.
The risk information submitted in support of the proposed changes to LCO 3.0.4 and SR 3.0.4 includes qualitative risk assessments performed by each owners group to identify higher risk systems and components at the various modes of operation, including transitions between modes, as the plant moves upward from the refueling mode of operation toward power operation. The owners groups generic qualitative risk assessments are included as attachments to TSTF-359, Revision 8. Each of the owners groups generic qualitative risk assessments discuss the technical approach used and the systems/components subsequently determined to be of higher risk significance; the systems/components not to be granted the LCO 3.0.4 allowances for the various modes are listed. The BWR owners groups generic qualitative risk assessments are:
BWR owners group Risk-Informed Technical Specification Committee, Technical Justification to Support Risk-Informed Improvements to Technical Specification Mode Restraints for BWR Plants, General Electric Company GE-NE A13-00464 (Rev. 2).
Following interactions with the NRC staff, all owners groups used the same systematic approach in their qualitative risk assessments to identify the higher-risk systems in the STS, consisting of the following steps:
identification of plant conditions (i.e., plant parameters and availability of key mitigation systems) associated with changes in plant operating modes while returning to power identification of key activities that have the potential to impact risk and which are in progress during transitions between modes while the plant is returning to power identification of applicable accident initiating events for each mode or other specified condition in the applicability identification of the higher-risk systems and components by combining the information in the first three steps (qualitative risk assessment)
The risk assessments properly used the results and insights from previous deterministic and probabilistic studies to systematically search for plant conditions in which certain key plant components are more important in mitigating accidents than during operation at power (Mode 1). This search was systematic, taking the following factors into account for the various stages of returning the plant to power:
the status of accident mitigation and normally operating systems the status of key plant parameters such as RCS pressure the key activities that are in progress during transitions between modes which have the potential to impact risk (e.g., the transfer from auxiliary to main feedwater at some PWR plants when Mode 1 is entered) the applicable accident initiating events for each mode of plant operation design and operational differences among plants or groups of plants The following systems and components were identified by the BWR Owners Group (BWROG) as higher-risk systems and components, when the plant is entering a new mode:
BWROG Plants System BWR Type Entering Mode High Pressure Coolant Injection (HPCI) System BWR 3 & 4 2, 1 High Pressure Core Spray (HPCS)
BWR 5 & 6 2, 1 Reactor Core Isolation Cooling (RCIC) System BWR 3, 4, 5 & 6 2, 1 Isolation Condenser BWR 2 2, 1 Diesel Generators (including other Emergency/Shutdown AC Power Supplies)
All All Hardened Wetwell Vent System BWR 2, 3 & 4 with Mark I Containment 3, 2, 1 RHR System All 4
If a licensee identifies a higher-risk system for only some of the modes of applicability, the TS for that system would be modified by a note that reads, for example, "LCO 3.0.4.b is not applicable when entering MODE 1 from MODE 2." Systems identified as higher risk for Modes 4 and 5 for BWRs, are also excluded from transitioning up to the mode of higher risk, and as previously discussed, notes for those transitions are superfluous. In addition, mode transitions for Modes 4 and 5 for BWRs, will be addressed by administrative controls.
Table 1 in SE Section 1.2, provides a summary of the changes proposed by the licensee.
The licensee has adopted the TSTF-359 wording for LCO 3.0.4 and SR 3.0.4. Existing notes stating that LCO 3.0.4 is not applicable have been deleted from various TS LCOs as described in TSTF-359 and the supporting documentation. The format and numbering of the RBS TS vary from the STS, but the changes proposed are consistent with TSTF-359 and this SE. LCO 3.0.4.c has been referenced appropriately for the TS defining limits on parameters and values. The licensee has, consistent with the Table 1 in SE Section 1.2, added notes to the appropriate TS to state that the revised LCO 3.0.4.b allowing mode changes with inoperable equipment is not applicable to the identified higher-risk systems.
In summary, the NRC staffs review of the BWROG's qualitative risk assessments finds that they are of adequate quality to support the application (i.e., they identify the higher-risk systems and components) associated with entering higher modes of plant operation with equipment inoperable while returning to power.
3.1.3 Limited Time in TS Required Actions Any temporary risk increase will be limited by, among other factors, duration constraints imposed by the TS CTs of the inoperable systems. For the systems and components which are not higher risk, any temporary risk increase associated with the proposed allowance will be smaller than what is considered acceptable when the same systems and components are inoperable at power. This is due to the fact that CTs associated with the majority of TS systems and components were developed for power operation and pose a smaller plant risk for action statement entries initiated or occurring at lower modes of operation as compared to power operation.
The LCO 3.0.4.b allowance will be used only when the licensee determines that there is a high likelihood that the LCO will be satisfied following the mode change. This will minimize the likelihood of additional temporary risk increases associated with the need to exit a mode due to failure to restore the unavailable equipment within the CT. In most cases, licensees will enter into a higher mode with the intent to move up to Mode 1 (power operation). As discussed in Section 3.2, the revised ROP monitors unplanned power changes as a performance indicator.
The ROP thus discourages licensees from entering a mode or other specified condition in the applicability of an LCO, and moving up in power, when there is a likelihood that the mode would have to be subsequently exited due to failure to restore the unavailable equipment within the CT. Another disincentive for licensees to enter a higher mode when an LCO is not met is related to reporting requirements. 10 CFR 50.72 and 50.73 make it clear that a report is required when a nuclear plant shutdown or mode change is required by TS. The NRCs oversight program will provide the framework for inspectors and other staff to follow the history at a specific plant of entering higher modes while an LCO is not met, and use such information in assessing the licensees actions and performance.
3.1.4 Cumulative Risk Increases The cumulative risk impact of the change to allow the plant to enter a higher mode of operation with one or more safety-related components unavailable (as proposed here), is measured by the average yearly risk increase associated with the change. In general, this cumulative risk increase is assessed in terms of both CDF and LERF (i.e., CDF and LERF, respectively).
The increase in CDF due to the proposed change is expressed by the following equation, which integrates the risk impact from all expected specified conditions (i.e., all expected plant conditions caused by mode changes with various TS systems and components unavailable).
=
j (CDFi) = j ICCDPi fi (2) where CDFi
=
the CDF increase due to specified condition i ICCDPi =
the ICCDP associated with specified condition i fi
=
the average yearly frequency of occurrence of specified condition i A similar expression can be used for LERF by substituting the measure of risk, i.e., LERF for CDF. The magnitude of the CDF and LERF values associated with plant conditions applicable to LCO 3.0.4.b allowances can be managed by controlling the temporary risk increases, in terms of both CDF and LERF (i.e., ICCDP and ICLERP), and the frequency (f), of each of such conditions. In addition to the points made in the previous section regarding temporary risk increases, the following points put into perspective how the key elements of the proposed risk-informed approach, used to justify an LCO 3.0.4.b allowance, are expected to prevent significant cumulative risk increases by limiting the frequency of its use:
The frequency of risk-significant conditions will be limited by not providing the LCO 3.0.4.b allowances to the higher risk systems and components.
The frequency of risk-significant conditions will be limited by the requirement to assess the likelihood that the LCO will be satisfied following the mode change.
The frequency of risk-significant conditions is limited by the fact that such conditions can occur only when the plant is returning to power following shutdown, i.e., during a small fraction of time per year (data over the past five years indicate that the plants are averaging 2.1 startups per year).
The addition of the proposed LCO 3.0.4.b allowances to the plant maintenance activities is not expected to change the plants average (cumulative) risk significantly.
3.1.5 Risk Assessment and Risk Management of Mode Changes With all safety systems and components operable, a plant can transition up in mode to power operation. With one or more system(s) or component(s) inoperable, this change permits a plant to transition up in mode to power operation if the inoperable system(s) or component(s) are not in the pre-analyzed higher risk category, a 10 CFR 50.65(a)(4) based risk assessment is performed prior to the mode transition, and the requisite risk management actions are taken.
The proposed TS Bases state, When an LCO is not met, LCO 3.0.4 also allows entering MODES or other specified conditions in the Applicability following assessment of the risk impact and determination that the impact can be managed. The risk assessment may use quantitative, qualitative, or blended approaches, and the risk assessment will be conducted using the plant program, procedures, and criteria in place to implement 10 CFR 50.65(a)(4), which requires that risk impacts of maintenance activities to be assessed and managed.
It should be noted that, the risk assessment, for the purposes of LCO 3.0.4.b, must take into account all inoperable TS equipment regardless whether the equipment is included in the licensees normal 10 CFR 50.65(a)(4) risk assessment scope. The risk assessments will be conducted using the procedures and guidance endorsed by RG 1.182. The results of the risk assessment shall be considered in determining the acceptability of entering the MODE or other specified condition in the Applicability, and any corresponding risk management actions. A risk assessment and establishment of risk management actions, as appropriate, are required for determination of acceptable risk for entering MODES or other specified conditions in the Applicability when an LCO is not met. Elements of acceptable risk assessment and risk management actions are included in Section 11 of Nuclear Management and Resources Council document (NUMARC) 93-01, Assessment of Risk Resulting from Performance of Maintenance Activities, as endorsed by RG 1.182, which addresses general guidance for conduct of the risk assessment, gives quantitative and qualitative guidelines for establishing risk management actions, and provides example risk management actions. These risk management actions include actions to plan and conduct other activities in a manner that controls overall risk, actions to increase risk awareness by shift and management personnel, actions to reduce the duration of the conditions, actions to minimize the magnitude of risk increases (establishment of backup success paths or compensatory measures), and actions to ensure that a determination is made that the proposed MODE change is acceptable.
The guidance references in RG 1.182, state that a licensees risk assessment process should be sufficiently robust and comprehensive to assess risk associated with maintenance activities during power operation, low power and shutdown conditions (all modes of operation), including changes in plant conditions. NUMARC 93-01 states that the risk assessment should include consideration of: (1) the degree of redundancy available for performance of the safety function(s) served by the out-of-service equipment, (2) the duration of the out-of-service condition, (3) component and system dependencies that are affected, (4) the risk impact of performing the maintenance during shutdown versus at power; and, (5) the impact of mode transition risk. For power operation, key plant safety functions are those that ensure the integrity of the reactor coolant pressure boundary, ensure the capability to shut down and maintain the reactor in safe shutdown condition, and ensure the capability to prevent or mitigate the consequences of accidents that could result in potentially significant offsite exposures.
While the inoperabilities permitted by the CTs of TS-required actions take into consideration the safety significance and redundancy of the system or components within the scope of an LCO, the CTs generally do not address or consider concurrent system or component inoperabilities in multiple LCOs. Therefore, the performance of the 10 CFR 50.65(a)(4) risk assessment which looks at the entire plant configuration is essential (and required) prior to changing operational mode. The 10 CFR 50.65(a)(4) based risk assessment will be used to confirm (or reject) the appropriateness of transitioning up in mode given the actual status of plant safety equipment.
The risk impact on the plant condition of invoking an LCO 3.0.4.b allowance will be assessed and managed through the program established to implement 10 CFR 50.65(a)(4). This program is consistent with RG 1.177 and RG 1.174 in its approach. The implementation guidance for paragraph (a)(4) of the Maintenance Rule addresses controlling temporary risk increases resulting from maintenance activities. This guidance, consistent with guidance in RG 1.177, establishes action thresholds based on qualitative and quantitative considerations and risk management actions. Significant temporary risk increases following an LCO 3.0.4.b allowance are unlikely to occur unless:
high-risk configurations are allowed (e.g., certain combinations of multiple component outages), or risk management of plant operation activities is inadequate.
The requirements associated with the proposed change are established to ensure that such conditions will not occur.
The thresholds of the cumulative (aggregate) risk impacts, assessed pursuant to 10 CFR 50.65(a)(4) and the associated implementation guidance, are based on the permanent change guidelines in NRC RG 1.174. Therefore, licensees will manage the risk exercising LCO 3.0.4 in conjunction with the risk from other concurrent plant activities to ensure that any increase, in terms of CDF and LERF) will be small and consistent with the Commissions Safety Goal Policy Statement.
3.2 Oversight The ROP provides a means for assessing the licensees performance in the application of the proposed mode change flexibility. The adequacy of the licensees assessment and management of maintenance-related risk is addressed by existing inspection programs and guidance for 10 CFR 50.65(a)(4). Although the current versions of that guidance do not specifically address application of the licensees 10 CFR 50.65(a)(4) program to support risk-informed technical specifications, it is expected that in most cases, risk assessment and management associated with risk-informed technical specifications would be required by 10 CFR 50.65(a)(4) anyway because maintenance activities will be involved.
Adoption of the proposed change will make failure to assess and manage the risk of an upward mode change with inoperable equipment covered by TSs, prior to commencing such a mode change, a violation of TSs. Further, as explained above in general, under most foreseeable circumstances, such a change in configuration would also require a risk assessment under 10 CFR 50.65(a)(4). Inoperable systems or components will necessitate maintenance to restore them to operability, and hence a 10 CFR 50.65(a)(4) risk assessment would be performed prior to the performance of those maintenance actions (except for immediate plant stabilization and restoration actions if necessary). Further, before altering the plants configuration, including plant configuration changes associated with mode changes, the licensee must update the existing 10 CFR 50.65(a)(4) risk assessment to reflect those changes.
The Federal Register Notice published on July 19, 1999 (64 FR 38553), issuing a revision to the Maintenance Rule, along with NRC Inspection Procedure (IP) 71111.13, and Section 11, of NUMARC 93-01, indicate that to determine the safety impact of a change in plant conditions during maintenance, a risk assessment must be performed before changing plant conditions.
The Bases for the proposed TS change mandate that the risk assessment and management of upward mode changes will be conducted under the licensees program and process for meeting 10 CFR 50.65(a)(4). Oversight of licensee performance in assessing and managing the risk of plant maintenance activities is conducted principally by inspection in accordance with ROP Baseline IP 71111.13. Supplemental IP 62709, Configuration Risk Assessment and Risk Management Process, is utilized to evaluate the licensees process, when necessary.
The overview of ROP is described in NUREG-1649, Rev. 3, Reactor Oversight Process, and in detail in the NRC Inspection Manual. IP 71111.13 requires verification of performance of risk assessments when they are required by 10 CFR 50.65(a)(4) and in accordance with licensee procedures. The procedure also requires verification of the adequacy of those risk assessments and verification of effective implementation of licensee-prescribed risk management actions. The rule itself requires such assessment and management of risk prior to maintenance activities, including preventive maintenance, surveillance and testing (and promptly for emergent work), during all modes of plant operation. The guidance documents for both industry implementation of (a)(4) and NRC oversight of that implementation indicate that changes in plant configuration (which would include mode changes) in support of maintenance activities must be taken into account in the risk assessment and management process.
Revisions to NRC inspection guidance and licensee implementation procedures will be needed to address oversight of risk assessment and management required by TS in support of mode changes that are not already required under the circumstances by (a)(4). This consideration provides performance-based regulatory oversight of the use of the proposed flexibility, and a disincentive to use the flexibility without the requisite care in planning.
In addition, the NRC staff has developed detailed SDP guidance in IMC 0609, Appendix K, dated May 19, 2005, for use in assessing inspection findings related to 10 CFR 50.65(a)(4).
The ROP considers inspection findings and performance indicators in evaluating licensee ability to operate safely. The SDP is used to determine the significance of inspection findings related to a licensee's assessment and management of the risk associated with performing maintenance activities under all plant operating or shutdown conditions. Unplanned reactor scrams and unplanned power changes are two of the Reactor Safety Performance Indicators that the ROP utilizes to assess licensee performance and inform the public. The ROP will provide a disincentive to entering into power operation (Mode 1), when there is a significant likelihood that the mode would have to be subsequently exited due to failure to restore the unavailable equipment within the CT.
3.3 Evaluation of Optional Changes, Variations, Verifications, and Commitments While the changes to TS Bases are not in the scope of the NRC staff's review, the staff finds that the licensee has performed the plant-specific verifications required by the notice of availability published in the Federal Register on April 4, 2003 (68 FR 16579), for this TS Improvement. Also, the Regulatory Commitment mentioned in 68 FR 16579 is not necessary because the RBS TSs already contain a TS Bases Control Program (TS 5.5.11) and SR 3.0.1.
The NRC staff has reviewed the licensees explanations for the Optional Changes and Variations described in Sections 1.1 and 1.3 of this SE, and finds them acceptable because they are consistent with the NRC-approved TSTF-359, Revision 9 and TSTF-485, Revision 0.
3.4 Summary - Technical Evaluation The industry, through the NEI RITSTF, has submitted a proposed TS change to allow entry into a higher mode of operation, or other specified condition in the TS applicability, while relying on the TS conditions, and associated required actions and CTs, provided a risk assessment is performed to confirm the acceptability of that action. The proposal revises TS LCO 3.0.4 and SR 3.0.4, and their application to the TS, including revisions to the notes in TS sections. New paragraphs (a), (b), and (c) are proposed for LCO 3.0.4.
The proposed LCO 3.0.4.a retains the current allowance, permitting the mode change when the TS required actions allow indefinite operation.
Proposed LCO 3.0.4.b is the change to allow entry into a higher mode of operation, or other specified condition in the TS applicability, while relying on the TS conditions and associated required actions and CTs, provided a risk assessment is performed to confirm the acceptability of that action for the existing plant configuration. The NRC staff review finds that the process proposed by the industry and the licensee for assessing and managing risk during the implementation of the proposed LCO 3.0.4.b allowances, meets Commission guidance for TS changes. Key elements of this process are listed below:
A risk assessment shall be performed before any LCO 3.0.4.b allowance is invoked.
The risk impact on the plant condition of invoking an LCO 3.0.4.b allowance will be assessed and managed through the program established to implement 10 CFR 50.65(a)(4) and the associated guidance in RG 1.182. Allowing entry into a higher mode or condition in the applicability of an LCO after an 10 CFR 50.65(a)(4) based risk assessment and appropriate risk management actions are taken for the existing plant configuration will ensure that plant safety is maintained.
The LCO 3.0.4.b allowance will be used only when the licensee determines that there is a high likelihood that the LCO will be satisfied within the required actions CT.
TS systems and components which may be of higher risk during mode changes have been identified generically by each owners group for each plant operational mode or condition. Licensees will identify such plant-specific systems and components in the individual plant TS. The proposed LCO 3.0.4.b allowance does not apply to these systems and components for the mode or condition in the applicability of an LCO at which they are of higher risk.
Plants adopting LCO 3.0.4.b will ensure that plant procedures in place to implement 10 CFR 50.65(a)(4) address the situation where entering a mode or other specified condition in the applicability is contemplated with plant equipment inoperable. Such plant procedures typically follow the guidance in NUMARC 93-01, Section 11, as revised in February 2000 and endorsed by NRC RG 1.182.
The NRCs ROP provides the framework for inspectors and other staff to oversee the implementation of 10 CFR 50.65(a)(4) requirements at a specific plant and assess the licensees actions and performance.
The LCO 3.0.4.b allowance does not apply to values and parameters of the TSs that have their own respective LCOs (e.g., RCS Specific Activity), but instead those values and parameters are addressed by LCO 3.0.4.c. The TS values and parameters for which mode transition allowances apply, will have a note that states LCO 3.0.4.c is applicable.
The objective of the proposed change is to provide additional operational flexibility without compromising plant safety.
Also, the proposed revisions to TS 1.4, Example 1.4-1, are acceptable to the NRC staff because they are consistent with the changes made to LCO 3.0.4.
3.5 Conclusion - Technical Evaluation The NRC staff has reviewed the licensee's application, dated July 2, 2007, using CLIIP, for an amendment to the FOL to modify: (1) RBS TS LCO 3.0.4, SR 3.0.4, and TS 1.4, Example 1.4-1, (2) the other appropriate TS sections, and (3) the optional changes, variations, Verifications, and Commitments regarding the required changes described in the NRC-approved TSTF-359 and TSTF-485. Based on the above discussions in Sections 1.0 through 3.4, the NRC staff finds that the licensee's proposed changes to RBS TS LCO 3.0.4, SR 3.0.4, and changes to other appropriate TS sections as described in the licensee's application, including the optional changes, variations, verifications, and commitments, are consistent with the NRC-approved model SE published in the notice of availability in the Federal Register on April 4, 2003 (68 FR 16579), and, therefore, the changes are acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Louisiana State official was notified of the proposed issuance of the amendment. The State official receiving the notification had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change SRs.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding published September 11, 2007 (72 FR 51856). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: A. J. Lising, NRR/ITSB Date: December 6, 2007