ML23341A154
| ML23341A154 | |
| Person / Time | |
|---|---|
| Site: | 07109196, 07109362 |
| Issue date: | 12/07/2023 |
| From: | Travis Tate Framatome |
| To: | Office of Nuclear Material Safety and Safeguards, Document Control Desk |
| References | |
| TJT:23:029 | |
| Download: ML23341A154 (1) | |
Text
framatome TJT:23:029 Page 1 of 6 December 7, 2023 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Director, Division of Fuel Management Office of Nuclear Material Safety and Safeguards Washington, D.C. 20555-001
Subject:
10 CFR 71.95 - 60 Day Report - SOB Cylinder Valve Installation
References:
(1) NRC Certificate of Compliance (CoC) USA/9362/AF-96, DN30 Packaging.
(2) NRC CoC USA/9196/B(U)F-96, UX-30 Packaging.
(3) ANSI N14.1 - 2012, Uranium Hexafluoride - Packagings for Transport.
Dear Sir or Madam,
Pursuant to 10 CFR 71.95(a)(3), Framatome Inc. (Framatome) submits this report for self-identification of instances where Framatome performed 306 cylinder valve installations that potentially exceeded the maximum allowable torque applied to the valves. These 306 cylinders are used to transport Uranium Hexafluoride in the DN30 and UX-30 outer protective packaging. These NRC licensed protective packagings rely on the 306 cylinder being maintained in accordance with ANSI N14.1 - 2012 as detailed in their Certificate of Compliance (CoC).
Framatome is not the certificate holder for this packaging. The certificate holders are:
DN30, USA/9362/AF-96 Orano NCS GmbH Margarete-von-Wrangell-Strafte 7 D-63457 Hanau - Germany o UX-30, USA/9196/8(U)F-96 TN Americas, LLC 7160 Riverwood Drive, Suite 200 Columbia, MD 21046 On October 16th, 2023, a Framatome inspector witnessed a cylinder recertification technician incorrectly use a torque wrench in a manner that may have exceeded the 400 ft-lbf allowed per ANSI N14.1. Through investigation, this improper practice was determined to be common.
framatome TJT:23:029 Page 2 of 6 The attachment to this letter provides the required details for the report.
Please feel free to contact me at (509) 375-8550 or Bryan Flanagan of my staff at (509) 375-8537 if you have questions or need additional information.
Sincerely, Timothy J. Tate, Manager Environmental, Health, Safety and Licensing TJT/sm Attachments: 10 CFR 71.95 - SOB Cylinder Valve Installation
framatome TJT:23:029 Page 3 of 6 Attachment 10 CFR 71.95 - 306 Cylinder Valve Installation
- 1. Brief abstract describing the major occurrences 71.95(c)(1)
The condition of approval for the UX-30 and DN30 protective shipping packaging (USA/9196/B(U)F-96 and USA/9362/AF-96 respectively) applies to the SOB cylinder being maintained in accordance with ANSI N14.1 -2012, Uranium Hexafluoride - Packagings for Transport.
On October 16th, 2023, during a SOB cylinder valve installation, the improper use of a torque wrench was observed which potentially exceeded the torque setting of the wrench. Through investigation, this improper practice was determined to be common. As a result of the improper use of a torque wrench, the maximum regulatory torque of 400 ft-lbf may have been slightly exceeded during the installation of SOB cylinder valves used to transport Uranium Hexafluoride.
Framatome provides 306 cylinder recertification services for the enriched uranium products industry. This issue potentially affects all SOB cylinders that have been through the five year periodic inspections and tests performed by Framatome at the Richland, WA facility.
There was no component or system failure that contributed to this event.
- 2. Narrative description of the event, 71.95(c)(2)
(i) Status of components or systems that were inoperable at the start of the event and that contributed to the event; The improper use of the torque wrench is a skill based and knowledge based personnel error. There were no inoperable components or systems.
(ii) Dates and approximate times of occurrences; The first observation of the improper use of the torque wrench occurred on October 16, 2023. Upon investigation, it was determined the three manufacturing technicians qualified for SOB cylinder valve installation all used the improper technique of continuing to apply force to the torque wrench after it clicked. The longest currently qualified manufacturing technician for cylinder recertification began in November 2021.
framatome TJT:23:029 Page 4 of 6 The frequency of the improper use of the torque wrench is not known. The manufacturing technicians would continue to apply force to the torque wrench when the valve was close to the final installation position of 6 oclock. This is standard practice, however, the torque wrench should have been reset (relaxing the applied force and repositioning) allowing the torque wrench to indicate again at the set value (384 ft-lbf).
(Hi) The cause of each component or system failure or personnel error, if known; The cause of the improper technique during use of the torque wrench is a skill based and knowledge based personnel error. The manufacturing technicians did not properly use the torque wrench.
The SOB cylinder valves have 1 inch National Pipe Threads (NPT) with tinning. The valves and tinning conform to the requirements specified in ANSI N14.1. In most cases, the valve is installed without reaching the 384 ft-lbf torque wrench setting.
Due to the tinning on the valve threads, it is possible to gain additional rotation of the valve after the initial click of the torque wrench. By releasing the pressure applied to the torque wrench by the technician, repositioning the wrench to the most optimal position for the technician, and reapplying slow constant pressure, a considerable amount of additional rotation is possible before the torque wrench clicks again at the torque setting (384 ft-lbf). This can be repeated several times until no movement is possible before the torque wrench clicks at the set torque. It is the releasing of pressure after the click and repositioning the torque wrench that the technicians failed to perform.
(iv) The failure mode, mechanism, and effect of each failed component, if known; A maximum of 400 ft-lbf of torque is specified by ANSI N14.1. Although not defined, it is assumed that this limit is established to prevent damage, first to the valve and second to the 30B cylinder. Framatome has been unable to determine the justification for the 400 ft-lbf limit or how it was established.
Framatome uses a maximum torque setting of 384 ft-lbf rather than the 400 ft-lbf to account for a 4% tolerance range of the equipment. This lower setting also assists with the conclusion that the valves are not affected by the misuse of the torque wrench.
framatome TJT:23:029 Page 5 of 6 (v) A list of systems or secondary functions that were also affected for failures of components with multiple functions; No systems or secondary functions were affected for failures.
(vi) The method of discovery of each component or system failure or procedural error; A Framatome inspector was witnessing the installation of a 306 cylinder valve and noticed the improper use of the torque wrench. Upon investigation with the two other manufacturing technicians, the improper use of the torque wrench was consistent with each technician.
(vii) For each human performance-related root cause, a discussion of the cause(s) and circumstances; The manufacturing technicians believed they were following the training received as a qualified operator which has been passed down from a long-time cylinder recertification operator. The long-time operator had been installing valves for many years and knew how perform the task, so the procedure seemed clear when the task was performed. A clear understanding and justification of the valve installation regulatory requirements did not exist among the manufacturing technicians.
(viii) The manufacturer and model number (or other identification) of each component that failed during the event; There were no component failures.
(ix) For events occurring during use of a packaging, the quantities and chemical and physical form(s) of the package contents.
No events occurred during use of a packaging.
- 3. Assessment of Safety Consequences and Implications of the Event, 71.95(c)(3)
There is no failure and no safety consequence resulting from potentially slightly exceeding the 400 ft-lbf allowable torque applied to the 306 cylinder valve. All 306 cylinder valves are leak tested at 100 psi following installation to confirm valve integrity. No domestic or foreign cylinder customer for which Framatome
framatome TJT:23:029 Page 6 of 6 has performed any cylinder service work has ever reported to Framatome any concern with the cylinder valve performance or integrity that could be related to an over torqued condition.
- 4. Corrective actions taken, 71.95(c)(4)
The following corrective actions were taken:
- Operating procedure detailing the installation of valves revised to better reflect ANSI N14.1 requirements and include correct use of a torque wrench.
© Manufacturing Technicians instructed on procedure changes and proper torque wrench operation.
- Stopped unsupervised cylinder valve installation while procedure update was in process and training completed.
- 5. Reference to any previous similar events, 71.95(c)(5)
There are no previous or similar events identified with this non-conformance.
- 6. Contact, 71.95(c)(6)
Please contact Timothy Tate at (509) 375-8550 for any additional information regarding this report.
- 7. Assessment of Safety Consequences an Implications of the Event, 71.95(c)(7)
No individuals were exposed to radiation or radioactive material due to this event.
There was no leakage of contents due to the non-conformance and no reduction in the performance of any packaging.