ML25343A364
| ML25343A364 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 12/11/2025 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Technical Specifications Task Force |
| References | |
| EPID L-2024-PMP-0011 | |
| Download: ML25343A364 (6) | |
Text
FINAL SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION TECHNICAL SPECIFICATIONS TASK FORCE TRAVELER TSTF-602, REVISION 0 REVISE THE VENTILATION FILTER TESTING PROGRAM TO PERMIT ALTERNATE CHALLENGE AGENTS USING THE CONSOLIDATED LINE ITEM IMPROVEMENT PROCESS (EPID L-2024-PMP-0011)
1.0 INTRODUCTION
By letter dated June 25, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24177A043), the Technical Specifications Task Force (TSTF) submitted TSTF Traveler TSTF-602, Revision 0, Revise the Ventilation Filter Testing Program to Permit Alternate Challenge Agents, to the U.S. Nuclear Regulatory Commission (NRC).
TSTF-602 proposed changes to the Standard Technical Specifications (STS) for boiling-water reactor (BWR) and pressurized-water reactor (PWR) designs under the consolidated line item improvement process (CLIIP). Upon approval, this traveler will be made available to nuclear power plant applicants and licensees for adoption, and the changes will be incorporated into future revisions of the following NRC STS1:
NUREG-1430, Standard Technical Specifications, Babcock and Wilcox Plants, Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21272A363 and ML21272A370, respectively).
NUREG-1431, Standard Technical Specifications, Westinghouse Plants, Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21259A155 and ML21259A159, respectively).
NUREG-1432, Standard Technical Specifications, Combustion Engineering Plants, Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21258A421 and ML21258A424, respectively).
NUREG-1433, Standard Technical Specifications, General Electric BWR/4 Plants, Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21272A357 and ML21272A358, respectively).
NUREG-1434, Standard Technical Specifications, General Electric BWR/6 Plants Volume 1, Specifications, and Volume 2, Bases, Revision 5, September 2021 (ML21271A582 and ML21271A596, respectively).
The proposed changes would revise the Ventilation Filter Testing Program (VFTP) to allow the use of alternative challenge agents when testing filters and charcoal adsorber beds.
1NUREG-1433 provides the STS for BWR/4 plant designs, but is also representative of the BWR/2, BWR/3, and, in this case, the BWR/5 plant design.
NUREG-1434 provides the STS for BWR/6 plant designs, but is also representative in some cases of the BWR/5 plant design.
1.1 Description of Ventilation Filter Testing Program in the STS Each of the STS contains testing programs for the ventilation filters which are referenced in surveillance requirements (SR) by the engineered safety feature (ESF) ventilation filter systems technical specifications (TS). The program is titled Ventilation Filter Testing Program (VFTP),
and is located at STS 5.5.10 in NUREG-1430, NUREG-1431, and NUREG-1432, and STS 5.5.7 in NUREG-1433 and NUREG-1434.The VFTP are standard programs to test the ESF ventilation filter systems.
The ESF ventilation filter system names may vary by plant, but generally include the Control Room Emergency Filtration System, Fuel Building Air Cleanup System, Iodine Cleanup System, Shield Building Air Cleanup System, Emergency Core Cooling System Pump Room Exhaust Air Cleanup System, Penetration Room Exhaust Air Cleanup System, and the Standby Gas Treatment System. These ESF ventilation filter individual system specifications contain an SR that requires filter testing in accordance with the VFTP at a Frequency in accordance with the VFTP in STS 5.5.10 or STS 5.5.7. The ESF ventilation systems associated with the control room provide a protected environment from which occupants can control the unit following an uncontrolled release of radioactivity, hazardous chemicals, or smoke. The remainder of the ESF ventilation filter systems reduce the airborne radioactive particulates released to the environment following an accident, through filtration and adsorption.
Industry codes and standards and NRC Regulatory Guides are referenced in the STS VFTP and plant-specific VFTP, such as:
NRC Regulatory Guide (RG) 1.52, Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident Engineered-Safety-Feature Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants, Revisions 2 (March 1978, ML003740139), and 3 (June 2001, ML011710176);
American National Standards Institute (ANSI) N510-1975 and -1980, Testing of Nuclear Air-Cleaning Systems; American Society of Mechanical Engineers (ASME) N510-1989 and -2007, Testing of Nuclear Air Treatment Systems; and ASME AG-1-2009, Code on Nuclear Air and Gas Treatment.
1.2 Proposed Changes to STS NUREG-1430 through NUREG-1432, STS 5.5.10, and NUREG-1433 and NUREG-1434, STS 5.5.7, would be revised to add a sentence allowing an alternative challenge agent in accordance with RG 1.52, Revision 3 (proposed additional wording in bold Italics):
- a.
Demonstrate for each of the ESF systems that an inplace test of the high efficiency particulate air (HEPA) filters shows a penetration and system bypass < [0.05]% when tested in accordance with [RG 1.52, Revision 2, and ASME N510-1989] at the system flowrate specified below [+/- 10%].
An alternative challenge aerosol may be used in accordance with Regulatory Guide 1.52, Revision 3, Section 6.3.
ESF Ventilation System Flowrate
[ ]
[ ]
- b.
Demonstrate for each of the ESF systems that an inplace test of the charcoal adsorber shows a penetration and system bypass < [0.05]%
when tested in accordance with [RG 1.52, Revision 2, and ASME N510-1989] at the system flowrate specified below [+/- 10%]. An alternative challenge gas may be used in accordance with Regulatory Guide 1.52, Revision 3, Section 6.4.
ESF Ventilation System Flowrate
[ ]
[ ]
Additionally, two editorial corrections were proposed. In NUREG-1432, VFTP paragraph b, the placeholder table for the ESF ventilation system name and flowrate was missing and is proposed to be added. In NUREG-1434, VFTP paragraphs a and b end with a colon instead of with a period as in the other STS. The colon is proposed to be replaced with a period.
1.3 Proposed Changes to the STS Bases The traveler did not propose any STS Bases changes.
2.0 REGULATORY EVALUATION
As stated in 10 CFR 50.36(a)(1), an application for a license authorizing operation of a production or utilization facility shall include proposed TS in accordance with the requirements in 10 CFR 50.36. The regulation further provides that a summary statement of the bases or reasons for such specifications, other than those covering administrative controls, shall also be included in the application, but shall not become part of the TS.
The regulations in 10 CFR 50.36, Technical specifications, require that the TSs include items, in part, in the following categories: (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation [LCOs]; (3) SRs; (4) design features; and (5) administrative controls.
The regulation at 10 CFR 50.36(c)(3) provides that SRs are requirements relating to test, calibration, or inspection to assure the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the LCO will be met.
The regulation at 10 CFR 50.36(c)(5) requires TS to include administrative controls, which are the provisions relating to organization and management, procedures, recordkeeping, review and audit, and reporting necessary to assure operation of the facility in a safe manner.
As described in the Commissions Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors (58 FR 39132, dated July 22, 1993), [t]he new STS should include greater emphasis on human factors principles in order to add clarity and understanding to the text of the STS, and provide improvements to the Bases Section of the Technical Specifications which provides the purpose for each requirement in the specification.
The improved vendor-specific STS were developed and issued by the NRC in September 1992.
The Summary Section of the Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors states, in part:
Implementation of the Policy Statement through implementation of the improved STS is expected to produce an improvement in the safety of nuclear power plants through the use of more operator-oriented Technical Specifications, improved Technical Specification Bases, reduced action statement induced plant transients, and more efficient use of NRC and industry resources.
Section IV, The Commission Policy, of the Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors states, in part:
The purpose of Technical Specifications is to impose those conditions or limitations upon reactor operation necessary to obviate the possibility of an abnormal situation or event giving rise to an immediate threat to the public health and safety by identifying those features that are of controlling importance to safety and establishing on them certain conditions of operation which cannot be changed without prior Commission approval.
[T]he Commission will also entertain requests to adopt portions of the improved STS [(e.g., TSTF-602)], even if the licensee does not adopt all STS improvements. The Commission encourages all licensees who submit Technical Specification related submittals based on this Policy Statement to emphasize human factors principles.
In accordance with this Policy Statement, improved STS have been developed and will be maintained for each NSSS [nuclear steam supply system] owners group. The Commission encourages licensees to use the improved STS as the basis for plant-specific Technical Specifications. [I]t is the Commission intent that the wording and Bases of the improved STS be used to the extent practicable.
The NRC staffs guidance for the review of TS is provided in NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water Reactor] Edition (SRP), Chapter 16.0, Technical Specifications, Revision 3, dated March 2010 (ML100351425). As described therein, as part of the regulatory standardization effort, the NRC staff has prepared STS for each of the LWR nuclear designs listed in Section 1.0 of this SE.
RG 1.52, Revision 2, provides guidance for complying with provisions in 10 CFR Part 50, Appendix A with regards to the design, inspection, and testing of air filtration and iodine adsorption units of ESF atmosphere cleanup systems in light water-cooled nuclear power plants. The current STS, namely NUREG-1430, -1431, -1432, -1433, and -1434, reference RG 1.52, Revision 2, for the VFTP.
RG 1.52, Revision 3, Regulatory Position C.6 provides guidance for in-place testing criteria.
Regulatory Positions C.6.3 and C.6.4 permit the usage of alternative challenge agents for HEPA filter and adsorber in-place leak testing respectively in accordance with ASME N510-1989, Testing of Nuclear Air Treatment Systems and Appendix TA-C of ASME AG-1-1997, Testing of Nuclear Air Treatment Systems.
3.0 TECHNICAL EVALUATION
The NRC staff reviewed Traveler TSTF-602, which proposed changes to NUREGs-1430, -1431,
-1432, -1433, and -1434. The regulatory framework the NRC staff used to determine the acceptability of the proposed changes consists of the requirements and guidance listed in Section 2.0 of this safety evaluation. The NRC staff reviewed the proposed changes to the STS for using alternative challenge agents to determine whether they are consistent with the guidance provided by industry standards and RG 1.52, Revision 3.
3.1 Alternative Challenge Agent TSTF-602 revises the VFTP to permit the use of alternate challenge agents when performing in-place testing of ESF ventilation system HEPA filters and charcoal adsorbers. The challenge agents recommended in RG 1.52, Revision 2, and referenced in the current STS are dioctyl phthalate (DOP) and R-11. DOP is a suspected carcinogen, and R-11 production was phased out in 1995. Reclaimed R-11 is available but at increasing cost and difficulty. Alternative challenge agents are listed in industry standards and NRC RG 1.52, Revision 3.
RG 1.52, Revision 3, Regulatory Position 6.3, provides an option to use alternative challenge agents for HEPA filter testing:
In accordance with ASME N510-1989 and Article TA-1000 of ASME AG-1-1997, the standard challenge aerosol used in the in-place leak testing of HEPA filters is polydisperse droplets of dioctyl phthalate (DOP), also known as di-2-ethylhexyl-phthalate (DEHP). The 0.3 micrometer monodisperse DOP aerosol is used for efficiency testing of individual HEPA filters by manufacturers and Filter Test stations. Alternative challenge agents may be used to perform in-place leak-testing of HEPA filters when their selection is based on the following.
(footnote omitted)
- 1. The challenge aerosol has the approximate light scattering droplet size specified in Article TA-1130 of ASME AG-1-1997.
- 2. The challenge aerosol has the same in-place leak test results as DOP.
- 3. The challenge aerosol has a similar lower detection limit, sensitivity, and precision as DOP.
- 4. The challenge aerosol causes no degradation of the HEPA filter or the other ESF air-cleaning system components under test conditions.
- 5. The challenge aerosol is listed in the Environmental Protection Agencys Toxic Substance Control Act (TSCA)2 inventory for commercial use.
RG 1.52, Revision 3, Regulatory Position C.6.4, states the following on charcoal adsorber testing:
In accordance with ASME N510-1989 and Section TA of ASME AG-1-1997, the standard challenge gas used in the in-place leak testing of adsorbers is Refrigerant-11 (trichloromonofluoromethane). Alternative challenge gases may be used to perform in-place leak testing of adsorbers, when their selection is based on meeting the characteristics specified in Appendix TA-C of ASME AG-1-1997.
2 Environmental Protection Agencys Toxic Substance Control Act (TSCA), Inventory for Commercial Use.
The TSTF states in its submittal that VFTP in most plants TS reference RG 1.52, Revision 2, issued in 1978, which describes both design and testing requirements that are acceptable to the NRC and references various design standards that were applicable at the time, such as ANSI N509-1976, Nuclear Power Plant Air-Cleaning Units and Components. Additionally, the TSTF states that RG 1.52, Revision 3, issued in 2001, references more recent design standards which are not applicable to most operating plants, such as ASME N509-1989, and ASME AG-1-1997, Code on Nuclear Air and Gas Treatment. The TSTF states that replacing all VFTP references that cite RG 1.52, Revision 2, with references to Revision 3 would not be consistent with the licensing and design basis for most plants. Therefore, the traveler limits the proposed use of RG 1.52, Revision 3, to the selection of alternative challenge agents.
The NRC staff finds that it is acceptable for plants that continue to reference RG 1.52, Revision 2, for VFTP and reference RG 1.52, Revision 3, only for the selection of alternative challenge agents. The NRC staff finds that the proposed change meets 10 CFR 50.36(c)(3) because plants SRs referencing the VFTPs will continue to verify the effectiveness of the ESF ventilation filter systems consistent with RG 1.52 guidance.
Allowing alternative challenge agents that are consistent with RG 1.52, Revision 3, guidance in the VFTP as amended will ensure operation of the facility in a safe manner because the alternative challenge agents are acceptable alternatives as discussed in RG 1.52, Revision 3.
The testing programs for the ventilation filters are referenced in SRs by the ESF ventilation filter systems TSs. The details of the VFTP are in the Administrative controls section of the TS.
Based on the above evaluation, the NRC staff finds that the changes to the VFTP assure operation of the facility in a safe manner Therefore, the NRC staff finds that the proposed change meets 10 CFR 50.36(c)(5).
4.2 Formatting of Proposed STS Change The NRC staff reviewed the format and content of the proposed change to STS in TSTF-602 and determined that the change is consistent with conventional terminology and with the format and usage rules embodied in the STS.
5.0 CONCLUSION
The NRC staff reviewed Traveler TSTF-602, which proposed changes to NUREG-1430, NUREG-1431, NUREG-1432, NUREG-1433, and NUREG-1434. Based on its review of TSTF-602, the NRC staff has determined that the use of alternative challenge agents in accordance with RG 1.52, Revision 3, provides reasonable assurance that HEPA filters and adsorbers will perform their safety functions. The NRC staff finds that the proposed changes meet the requirements of 10 CFR 50.36(c)(3) and (c)(5). The STS, as modified by TSTF-602, will continue to specify the requirements for administrative controls and assure operation of the facility in a safe manner. Therefore, the NRC staff concludes that the proposed changes are acceptable.
Principal Contributors: J. Wilson, NRR/DSS H. Wagage, NRR/DSS R. Atienza, NRR/DSS Date: December 11, 2025