ENS 43166
ENS Event | |
|---|---|
05:00 Dec 11, 2006 | |
| Title | Part 21 Concerning Material Verifications on High Pressure and Temperature Steam and Water Globe Valves |
| Event Description | During a Nuclear Utilities Group Audit (NUPIC) on December 11, 2006, several problems were identified at CONVAL related to valve material verification. The problems relate to material verification for 1/2 inch to 4 inch forged body high pressure and temperature steam and water valves produced by this vendor. Since the audit, CONVAL has examined the issues and determined that they are reportable under 10 CFR 21.
Issue 1: CONVAL states that the pressure boundary material of the valves in question was not procured to ASME Section III, NCA-3800 program. CONVAL states that the valve material was procured as specified with Certified Material Test Reports (CMTRs) and some independent material over-checking and chemical analysis but the formal verification of the material did not meet NCA-3800. Issue 2: CONVAL states that there was also improper material verification of a safety related part within these valves. The split ring, which retains the closure disc to the stem within these valves, had inadequate material verifications performed for those valves that were ordered to Appendix B with upgraded material verifications. In this case, the split rings have CMTRs but no additional over-checks of the material were performed by CONVAL. None of the valves identified in issues 1 or 2 above were ordered with N-Stamps. CONVAL believes that up to 20 nuclear plants may possess these valves. CONVAL noted that their material verification process has remained unchanged for many years so that this is not a new or recent development. Issue 3: While performing the engineering analysis related to the two issues identified above, CONVAL also determined that under a worst case combination of physical properties for the split ring material in combination with worst case stress conditions, that split ring may not perform its function. CONVAL believes that the likelihood of the split ring failing under these extreme conditions is very remote. CONVAL does not believe there is any safety concern associated with these issues. CONVAL is in the process of identifying and notifying the affected customers. CONVAL plans to provide all customers and the NRC formal documentation of the nature of these Part 21 related deficiencies within the next five business days. |
| Where | |
|---|---|
| Conval, Inc Somers, Connecticut (NRC Region 1) | |
| Organization: | Conval, Inc |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+1570.08 h65.42 days <br />9.346 weeks <br />2.151 months <br />) | |
| Opened: | Donald Curtin 15:05 Feb 14, 2007 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Feb 14, 2007 |
| 43166 - NRC Website | |
Conval, Inc with 10 CFR 21.21 | |
WEEKMONTHYEARENS 431662006-12-11T05:00:00011 December 2006 05:00:00
[Table view]10 CFR 21.21 Part 21 Concerning Material Verifications on High Pressure and Temperature Steam and Water Globe Valves 2006-12-11T05:00:00 | |