ML18241A083
| ML18241A083 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 12/06/2018 |
| From: | Victor Cusumano NRC/NRR/DSS/STSB |
| To: | Technical Specifications Task Force |
| Honcharik M, NRR/DSS, 301-415-1774 | |
| Shared Package | |
| ML18241A087 | List: |
| References | |
| EPID L-2017-PMP-0025 | |
| Download: ML18241A083 (7) | |
Text
1 DRAFT SAFETY EVALUATION 2
3 BY THE OFFICE OF NUCLEAR REACTOR REGULATION 4
5 TECHNICAL SPECIFICATIONS TASK FORCE TRAVELER 6
7 TSTF-557, REVISION 1, 8
9 SPENT FUEL STORAGE RACK NEUTRON ABSORBER MONITORING PROGRAM 10 11 USING THE CONSOLIDATED LINE ITEM IMPROVEMENT PROCESS 12 13 (EPID L-2017-PMP-0025) 14 15 16
1.0 INTRODUCTION
17 18 By letter dated December 19, 2017 (Agencywide Documents Access and Management System 19 (ADAMS) Accession No. ML17353A608), the Technical Specifications Task Force (TSTF) 20 submitted Technical Specifications Task Force (TSTF) Traveler TSTF-557, Revision 1, Spent 21 Fuel Storage Rack Neutron Absorber Monitoring Program. Traveler TSTF-557 proposes 22 changes to the Standard Technical Specifications (STS) for all plant designs, including Babcock 23 and Wilcox, Combustion Engineering, Westinghouse, General Electric, and Westinghouse 24 AP1000 plants. These changes will be incorporated into future revisions of NUREG-1430, 25 NUREG-1431, NUREG-1432, NUREG-1433, NUREG-1434, and NUREG-2194.1 This traveler 26 will be made available to licensees for adoption through the consolidated line item improvement 27 process.
28 1
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Babcock and Wilcox Plants, NUREG-1430, Revision 4.0, April 2012, Volume 1, Specifications (ADAMS Accession No. ML12100A177), and Volume 2, Bases (ADAMS Accession No. ML12100A178).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Westinghouse Plants, NUREG-1431, Revision 4.0, April 2012, Volume 1, Specifications (ADAMS Accession No. ML12100A222), and Volume 2, Bases (ADAMS Accession No. ML12100A228).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Combustion Engineering Plants, NUREG-1432, Revision 4.0, April 2012, Volume 1, Specifications (ADAMS Accession No. ML12102A165), and Volume 2, Bases (ADAMS Accession No. ML12102A169).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, General Electric Plants, BWR/4, NUREG-1433, Revision 4.0, April 2012, Volume 1, Specifications (ADAMS Accession No. ML12104A192), and Volume 2, Bases (ADAMS Accession No. ML12104A193).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, General Electric Plants, BWR/6, NUREG-1434, Revision 4.0, April 2012, Volume 1, Specifications (ADAMS Accession No. ML12104A195), and Volume 2 (ADAMS Accession No. ML12104A196).
U.S. Nuclear Regulatory Commission, Standard Technical Specifications, Westinghouse Advanced Passive 1000 (AP1000) Plants, NUREG-2194, Revision 0, April 2016, Volume 1, Specifications (ADAMS Accession No. ML16110A277), and Volume 2, Bases (ADAMS Accession No. ML16110A369).
Enclosure 1
1 The proposed changes would add a new program entitled, Spent Fuel Storage Rack Neutron 2 Absorber Monitoring Program. The purpose of the program is to ensure the boron-10 areal 3 density of the neutron absorber material assumed in the spent fuel pool (SFP) storage rack 4 nuclear criticality analyses remains conservative with respect to the actual plant conditions. The 5 program is optional and may be adopted by licensees that have licensing requirements for a 6 SFP neutron absorber material (NAM) monitoring program.
7 8
2.0 REGULATORY EVALUATION
9 10
2.1 DESCRIPTION
OF SPENT FUEL POOL STORAGE RACKS 11 12 The credited NAM installed in the SFP storage racks ensures that the effective multiplication 13 factor (k-effective, keff) does not exceed the values and assumptions used in the criticality 14 analysis of record (AOR) and other licensing basis documents. The AOR is the basis, in part, 15 for demonstrating compliance with plant technical specifications (TS) and with applicable NRC 16 regulations. Degradation or deformation of the credited NAM may reduce safety margin and 17 potentially challenge the subcriticality requirement. The NAM utilized in SFP racks exposed to 18 treated water or treated borated water may be susceptible to reduction of neutron absorbing 19 capacity, changes in dimension that increase keff, and loss of material. A monitoring program is 20 implemented to ensure that degradation of the NAM used in SFPs, which could compromise the 21 ability of the NAM to perform its safety function as assumed in the AOR, will be detected.
22 23
2.2 PROPOSED CHANGE
S TO THE STANDARD TECHNICAL SPECIFICATIONS 24 25 A new program would be added to Section 5.5, Program and Manuals. The new program 26 would appear in each STS NUREG as:
27 28 5.5.XX [Spent Fuel Storage Rack Neutron Absorber Monitoring Program 29 30 This Program provides controls for monitoring the condition of the 31 neutron absorber used in the spent fuel pool storage racks to 32 verify the Boron-10 areal density is consistent with the 33 assumptions in the spent fuel pool criticality analysis. The 34 program shall be in accordance with NEI 16-03-A, Guidance for 35 Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, 36 Revision 0, May 2017[, with the following exceptions:
37 38 1. ].]
39 40 2.3 APPLICABLE REGULATORY REQUIREMENTS AND GUIDANCE 41 42 Section IV, The Commission Policy, of the Final Policy Statement on Technical Specifications 43 Improvements for Nuclear Power Reactors, published in the Federal Register on July 22, 1993 44 (58 FR 39132), states, in part:
45 46 The purpose of Technical Specifications is to impose those 47 conditions or limitations upon reactor operation necessary to 48 obviate the possibility of an abnormal situation or event giving rise 49 to an immediate threat to the public health and safety by 50 identifying those features that are of controlling importance to
1 safety and establishing on them certain conditions of operation 2 which cannot be changed without prior Commission approval.
3 4 [T]he Commission will also entertain requests to adopt portions 5 of the improved STS [(e.g., TSTF-557)], even if the licensee does 6 not adopt all STS improvements. The Commission encourages 7 all licensees who submit Technical Specification related submittals 8 based on this Policy Statement to emphasize human factors 9 principles.
10 11 In accordance with this Policy Statement, improved STS have 12 been developed and will be maintained for each NSSS [nuclear 13 steam supply system] owners group. The Commission 14 encourages licensees to use the improved STS as the basis for 15 plant-specific Technical Specifications. [I]t is the Commission 16 intent that the wording and Bases of the improved STS be used 17 to the extent practicable.
18 19 As described in the Commissions Final Policy Statement on Technical Specifications 20 Improvements for Nuclear Power Reactors, the NRC and industry task groups for new STS 21 recommended that improvements include greater emphasis on human factors principles in order 22 to add clarity and understanding to the text of the STS, and provide improvements to the Bases 23 of STS, which provides the purpose for each requirement in the specification. The improved 24 vendor-specific STS were developed and issued by the NRC in September 1992.
25 26 The regulation at Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(b) 27 requires:
28 29 Each license authorizing operation of a utilization facility will 30 include technical specifications. The technical specifications will 31 be derived from the analyses and evaluation included in the safety 32 analysis report, and amendments thereto, submitted pursuant to 33 [10 CFR] 50.34 [Contents of applications; technical information].
34 The Commission may include such additional technical 35 specifications as the Commission finds appropriate.
36 37 The regulation at 10 CFR 50.36(c)(5) requires TS to include administrative controls, which are 38 the provisions relating to organization and management, procedures, recordkeeping, review and 39 audit, and reporting necessary to assure operation of the facility in a safe manner.
40 41 The regulation in paragraph (b)(4) of 10 CFR 50.68, Criticality accident requirements, states 42 that if the licensee does not credit soluble boron in the SFP criticality AOR, the keff of the SFP 43 storage racks must not exceed 0.95 at a 95 percent probability, 95 percent confidence level if 44 flooded with unborated water. If the licensee does take credit for soluble boron, the keff of the 45 SFP storage racks must not exceed 0.95 at a 95 percent probability, 95 percent confidence 46 level, if the racks are flooded with borated water, and if flooded with unborated water, the keff 47 must remain below 1.0 at a 95 percent probability, 95 percent confidence level.
48 49 The STS Section 5.5 program imposes a requirement to have a licensee-controlled program 50 that is in accordance with Nuclear Energy Institute (NEI) topical report NEI 16-03-A, Guidance 51 for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools, Revision 0, dated May 26, 2017
1 (ADAMS Accession No. ML17263A133). The NRC staff approved NEI 16-03 in a safety 2 evaluation (SE) dated March 3, 2017 (ADAMS Accession No. ML16354A486). The 3 NEI 16-03-A topical report and the NRCs SE for NEI 16-03 provide the technical justification for 4 the proposed program.
5 6 The NRC staffs guidance for the review of TS is in Chapter 16.0, Technical Specifications, of 7 NUREG-0800, Revision 3, Standard Review Plan for the Review of Safety Analysis Reports for 8 Nuclear Power Plants, LWR [Light-Water Reactor] Edition (SRP), March 2010 (ADAMS 9 Accession No. ML100351425). As described therein, as part of the regulatory standardization 10 effort, the NRC staff has prepared STS for each of the LWR designs. Accordingly, the NRC 11 staffs review includes consideration of whether the proposed changes are consistent with the 12 applicable reference STS (i.e., the current STS), as modified by NRC-approved travelers. In 13 addition, the guidance states that comparing the change to previous STS can help clarify the TS 14 intent 15 16 Section 9.1.1, Revision 3, of the SRP, Criticality Safety of Fresh and Spent Fuel Storage and 17 Handling, March 2007 (ADAMS Accession No. ML070570006), provides guidance regarding 18 the acceptance criteria and review procedures to ensure that the proposed changes satisfy the 19 requirements in 10 CFR 50.68.
20 21 Section 9.1.2, Revision 4, of the SRP, New and Spent Fuel Storage (ADAMS Accession 22 No. ML070550057), provides guidance regarding the acceptance criteria and review procedures 23 to ensure that the proposed changes satisfy the requirements in 10 CFR 50.68.
24 25 NUREG-1801, Revision 2, Generic Aging Lessons Learned (GALL) Report, December 2010 26 (ADAMS Accession No. ML103490041), provides guidance on what constitutes an acceptable 27 monitoring program for NAM credited for criticality control in the SFP.
28 29
3.0 TECHNICAL EVALUATION
30 31 The NRC staff reviewed the proposed changes to STS and the technical justification for the 32 changes provided in Traveler TSTF-557. The NRC staff reviewed the technical justification for 33 the proposed changes to ensure the reasoning was logical, complete and clearly written as 34 described in Chapter 16 of NUREG-0800. The NRC staff reviewed the proposed changes for 35 consistency with conventional terminology and with the format and usage rules embodied in the 36 STS. The NRC staff also reviewed the STS changes to ensure adoption of the traveler by 37 future applicants would provide assurance that an applicants TS would continue to comply with 38 the requirements of 10 CFR 50.36. Finally, NRC staff also reviewed the changes to ensure any 39 limitations or conditions placed on adoption of the traveler by future applicants were clearly 40 described.
41 42 3.1 NEW PROGRAM FOR MONITORING NEUTRON ABSORBER 43 44 The purpose of the program is to ensure the boron-10 areal density of the neutron absorber 45 material assumed in the SFP storage rack nuclear criticality analyses remains conservative with 46 respect to the actual plant conditions.
47 48 The TS Section [5.5] program imposes a requirement to have a licensee-controlled program that 49 is in accordance with NEI 16-03-A, Guidance for Monitoring of Fixed Neutron Absorbers in 50 Spent Fuel Pools, Revision 0, May 2017. In the SE for NEI 16-03, dated March 3, 2017, the 51 NRC approved and accepted the document for referencing in licensing applications for nuclear
1 power plants. The NEI 16-03-A topical report and the NRCs SE for NEI 16-03 provide the 2 technical justification for the proposed program.
3 4 The purpose of a NAM monitoring program is to verify that the NAM installed in SFPs continues 5 to perform its safety function (i.e., criticality control) as assumed in the AOR. The guidance 6 provided in NEI 16-03-A for a NAM monitoring program relies on periodic inspection, testing, 7 monitoring, and analysis of the NAM to ensure that the required subcriticality margin is 8 maintained in accordance with 10 CFR 50.68 requirements. To accomplish this purpose, the 9 guidance document states that a monitoring program must be capable of identifying 10 unanticipated changes in the absorber material and determining whether anticipated changes 11 can be verified. The guidance recommends a combination of coupon testing, in situ 12 measurement, and SFP water chemistry monitoring as a means to monitor potential changes in 13 characteristics of the NAM. The NRC staff reviewed the proposed guidance for what constitutes 14 an acceptable monitoring program and its ability to ensure that potential degradation of SFP 15 NAM will be detected, monitored, and mitigated.
16 17 In the NRC staffs SE of NEI 16-03, the staff determined that an appropriate combination of the 18 three methods listed above (coupon testing, in situ measurement, and SFP water chemistry 19 monitoring) as described in NEI 16-03-A, can comprise an effective NAM monitoring 20 program. Section 3.4 of the NRCs SE of NEI 16-03 states that in order for a NAM program to 21 be acceptable, a licensee must perform neutron attenuation testing to verify the boron-10 areal 22 density. Further, in Section 4.0 of the NRC staffs SE of NEI 16-03, the staff concluded that a 23 NAM monitoring program implementing the guidance in NEI 16-03-A provides reasonable 24 assurance that such program will be able to detect degradation of neutron absorbing material, 25 and provides assurance that the ability of the NAM to provide the criticality control relied upon in 26 the AOR, is maintained. As noted above, the topical report NEI 16-03-A and the NRC staffs SE 27 approving NEI 16-03 provide the technical justification for the proposed program in TSTF-557.
28 29 The NRC staff reviewed the technical justification in TSTF-557 and determined it was logical, 30 complete, and clearly written as described in Chapter 16 of NUREG-0800. The NRC staff 31 further notes that the NRCs approval of TSTF-557 will allow licensees to more readily 32 incorporate an acceptable NAM monitoring program into their TS.
33 34 3.2 FORMATTING OF PROPOSED PROGRAM 35 36 The specification is in brackets, indicating that its applicability is plant-specific. A monitoring 37 program is only applicable to plants that credit NAM in their SFP criticality analysis. In addition, 38 plants may have been approved for use of NAM without a TS monitoring program, or may have 39 adopted alternate TS or license condition monitoring requirements. Likewise, brackets are used 40 to denote optional provisions for a licensee to request exceptions to NEI 16-03-A.
41 42 The NRC staff reviewed the format and content of the proposed change to STS in TSTF-557 43 and determined that the change is consistent with conventional terminology and with the format 44 and usage rules embodied in the STS.
45 46 3.3 CONTINUED COMPLIANCE WITH THE REQUIREMENTS OF 10 CFR 50.36 47 48 Adoption of the STS changes proposed in TSTF-557 by future applicants should provide 49 assurance that an applicants TS would continue to comply with the requirements of 50 10 CFR 50.36. Based on its review, the NRC staff determined that implementation of a 51 monitoring program into the TS, as described in TSTF-557, meets the regulatory requirements
1 and provides reasonable assurance that plants adopting these TS will have the requisite 2 requirements to continue to meet 10 CFR 50.36.
3 4 3.4 MODEL LICENSE AMENDMENT 5
6 A model license amendment application was included in Traveler TSTF-557. It is anticipated 7 that licensees may request adoption of the proposed change as part of a larger license 8 amendment request related to SFP storage and a revised SFP critical analysis. However, the 9 model may be used by licensees desiring to voluntarily adopt the traveler. The model includes 10 appropriate bracketed sections to accommodate plant-specific information as well as requests 11 for plant-specific exceptions and required justifications. The model also includes a reviewers 12 note to prompt licensees to include appropriate required information to fully describe and justify 13 any variations from the model.
14 15 The NRC staff reviewed the model license amendment application and determined that 16 limitations or conditions placed on adoption of the traveler by future applicants are clearly 17 described.
18 19
4.0 CONCLUSION
20 21 The NRC staff reviewed Traveler TSTF-557, which proposed changes to NUREG-1430, 22 NUREG-1431, NUREG-1432, NUREG-1433, NUREG-1434, and NUREG-2194. The NRC staff 23 determined that the proposed changes to the STS meet the standards for TS in 24 10 CFR 50.36(b). The regulations at 10 CFR 50.36 require that TS include items in specified 25 categories, including administrative controls.
26 27 Based on its review of TSTF-557 and previous approval of NEI 16-03, the NRC staff has 28 determined that a NAM monitoring program meeting the provisions in NEI 16-03-A will allow a 29 licensee to reasonably ensure that the ability of the NAM to perform its safety function, as 30 assumed in the AOR, is maintained, thus demonstrating compliance with the subcriticality 31 requirements of 10 CFR 50.68. The NRC staff finds that the proposed new monitoring program, 32 as adopted by licensees, will allow a licensees TS to continue to meet the requirements of 33 10 CFR 50.36(c)(5). The STS, as modified by TSTF-557, will continue to specify the 34 requirements for administrative controls. The NRC staff also concluded that the traveler and 35 model application contain appropriate limitations or conditions for adoption of the traveler by 36 future applicants.
37 38 Additionally, the changes to the STS were reviewed and found to be technically clear and 39 consistent with customary terminology and format in accordance with SRP Chapter 16.0. The 40 NRC staff reviewed the proposed changes against the regulations and concludes that the 41 changes continue to meet the requirements of 10 CFR 50.36(b), 50.36(c)(5), and 50.68, for the 42 reasons discussed above, and thus provide reasonable assurance that adoption of these 43 changes will have the requisite requirements and controls to operate safely. Therefore, the 44 NRC staff concludes that the proposed changes are acceptable.
45 46 Principal Contributors: M. Hamm, NRR/DSS 47 M. Yoder, NRR/DLMR 48 49 Date: