ML25015A018
| ML25015A018 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 12/19/2024 |
| From: | Hopkins M Nuclear Utility Group on Environmental Qualification (NUGEQ), Winston & Strawn, LLP |
| To: | Geoffrey Miller NRC/RGN-IV/DORS |
| References | |
| IR 2024003 | |
| Download: ML25015A018 (1) | |
Text
1 NUCLEAR UTILITY GROUP ON EQUIPMENT QUALIFICATION WINSTON & STRAWN LLP 1901 L STREET, N.W.
WASHINGTON, D.C. 20036-3506 TELEPHONE (202) 282-5737 December 19, 2024 Geoffrey B. Miller, Director Region 4 Division of Operating Reactor Safety 1600 East Lamar Boulevard Arlington, Texas 76011-4511 Re: NUGEQs Concern with Generic Implications and Request for Clarification Stemming from the Assessment of Performance Deficiency under Cooper Nuclear Station Integrated Inspection Report 05000298/2024003 as a 10 C.F.R. § 50.49 Non-Cited Violation (NCV)
Dear Mr. Miller:
The Nuclear Utility Group on Equipment Qualification (NUGEQ or Group)1 hereby submits this letter as a result of the Groups review of the Green Finding and NCV2 levied against Cooper Nuclear Station on November 5, 2024. Inspection Report 05000298/20240033 identified a performance deficiency associated with a violation of 10 C.F.R. 50.49, Environmental Qualification of Electric Equipment Important to Safety for Nuclear Power Plants, for the licensees failure to properly maintain environmental qualification of process line joints within the environmental qualification boundaries. Specifically, the inspection report identifies that a non-qualified thread sealant was used on instrument line joints associated with nuclear instrumentation and goes on to state that the licensee is required to use qualified or to qualify thread sealants used in environmental qualification boundaries by one of the methods described in § 50.49(f).
Specifically, our concern centers on how the NCV expands the applicability of 10 C.F.R. 50.49 to include process line fittings to mechanical components that are beyond the connection interface with the EQ equipment. The description of the NCV in the inspection report 20240034 indicates that:
The licensee justified the use of non-qualified sealant by defining a boundary between the 1 The Group represents approximately 75% of the operating nuclear power plants in the United States. The Group was founded in 1981, as the NRC staff was evaluating and planning the ultimate promulgation of 10 C.F.R. 50.49, Environmental qualification of electric equipment important to safety for nuclear power plants.
2 NCV 2024003-01, Failure to Maintain Environmental Qualification of Process Line Connections Associated with Safety-Related Instrumentation.
3 Accession No. ML24291A261.
4 NCV 2024003-01 differs from the previous 50.49(f) violation issued to Cooper under inspection report 2024002 because the performance deficiency in question can exist independently from whether the Rosemount transmitters have either the welded Swagelok' or the optional 1/4-18 NPT process flange connection. NCV 05000298/2024002-01, Failure to Evaluate Safety-Related Rosemount Transmitters for Environmental Qualification specifically addressed the qualification of the optional 1/4-18 NPT process flange connection at the equipment boundary.
ADAMS Accession # ML25015A018
Geoffrey B. Miller December 19, 2024 2
EQ and non-EQ as the point of connection, or where the process line tubing threads into an EQ device. Additionally, the licensee stated that the electrical transmitter, electrical conduit seal assembly, and thread sealant at the connection of the process line to the host transmitter are the only components within the bounds of their EQ program. The licensee does not have documentation adequately supporting the qualification of Teflon by testing or other acceptable methods.
The thread sealant used on the NPT fittings that connect the process sensing lines to the electrical transmitters is not Teflon' tape and the qualified status of this thread sealant has not been challenged by this NCV. The use of Teflon' tape includes applications that seal the NPT threads at fittings on 3-valve manifolds, which is a mechanical component that is not integral to the transmitter (See Attachment A, Figures 1, 2, and 3).
It is NUGEQs position that NCV 2024003-01 represents a new staff position that expands the equipment scope of the EQ final rule as defined by § 50.49(b). As a result, this specific violation has generic implications in that it could be considered as a precedent in future inspections of other licensees in which inspectors are reviewing the thread sealants used to seal NPT fittings on mechanical components such as 3-valve manifolds that are located remotely from the transmitter.
The Group takes no formal position on whether a performance deficiency exists relative to how the licensee demonstrated conformance to the applicable design requirements for thread sealants used in process sensing lines. From a generic perspective, however, the Group is concerned with the implications of expanding the scope of 10 C.F.R. 50.49 to include connections to mechanical equipment that are external or physically remote from the specific connections and interfaces at the boundary of the electric equipment being environmentally qualified.
Without further clarification, the ramifications of this violation have the potential to significantly increase the scope of equipment subject to 10 CFR 50.49 by requiring the inclusion of mechanical equipment with NPT connections, including but not limited to:
- Hydraulic Operated Valves
- Pneumatic lines associated with Air Operated Valves
- Manual vent and drain valves
- 3-valve or 5-valve manifolds
- Excess flow check valves Request for Clarification Given the generic implications of NCV 2024003-01 citing the performance deficiency against § 50.49(f), the Group requests Staff clarification that § 50.49 does not apply to purely mechanical components (e.g., 3-valve manifolds, vent/drain valves, etc.) or their fittings including any thread sealant that are external to the connection interfaces of the electric or electro-mechanical equipment subject to § 50.49.
Geoffrey B. Miller December 19, 2024 3
We request this letter and any subsequent communications be placed into the public Agencywide Documents Access and Management System. We look forward to opportunities to discuss this issue with you at your convenience.
Respectfully, Matthew Hopkins Associate, Winston & Strawn LLP Counsel to NUGEQ 1901 L Street, NW Washington, DC 20036 phone: (202) 282-5862 email: mhopkins@winston.com Attachments: (1) cc (via email):
Michael C. Hay, Deputy Director R-IV DORS Michael.Hay@nrc.gov Nickolas Taylor, Deputy Director R-IV DORS Nick.Taylor@nrc.gov Douglas Dodson, Chief, Branch 2/R-IV Douglas.Dodson@nrc.gov Gregory Kolcum, SRI Gregory.Kolcum@nrc.gov Kent Chambliss, SRI Kent.Chambliss@nrc.gov Geoffrey Birkemeier, SRI Geoffrey.Birkemeier@nrc.gov Matt McConnell, NRR/ELTB/DEX Matthew.McConnell@nrc.gov
Attachment A - Page 1 ATTACHMENT A Location of Teflon' Tape Applications with Rosemount Transmitters
Attachment A - Page 2 The NCV addresses the use of Teflon' tape to seal the NPT threads where the process sensing lines connect to the 3-valve manifold. For a differential pressure transmitter application, the 3-valve manifold consists of a normally open high pressure block valve, a normally open low pressure block valve, and a normally closed equalizing valve between the high and low pressure sensing lines. The NCV has concluded that the Teflon' tape is used to seal the NPT threads at the 3-valve manifold is subject to the provisions of 10 C.F.R. 50.49.
Below are three Figures that depict exemplary valve manifolds.
Figure 1 depicts a typical connection diagram that shows the use of a standalone 3-valve manifold with a differential pressure transmitter.
Figure 1-Connection Diagram Figure 2 shows the location of where thread sealants are used to seal the NPT threaded connections on a 3-valve manifold Figure 2 valve manifold NPT ports where the sensing lines connect to a 3-valve manifold
Attachment A - Page 3 Figure 3 presents a typical installation of a Rosemount 1153 Series B transmitter with an associated 5-valve manifold. The 5-valve manifold, circled in the Figure below, is a mechanical equipment item that is not subject to the provisions of 10 CFR 50.49.
Figure 3 - Example installation of transmitter and associated manifold Rosemount 1153B Transmitter 5-valve manifold