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