Part 21 Report - 1997-241

ACCESSION #: 9703180058 United States Enrichment Corporation USEC 2 Democracy Center United States 6903 Rockledge Drive Enrichment Corporation Bethesda, MD 20817 James H. Miller Dir: (301) 564-3309 Vice President, Production Fax: (301) 564-3201 March 14, 1997 SERIAL: GDP 97-0036 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP) Docket No. 70-7001 Initial Notification of 10 CFR 21 Report The purpose of this letter is to provide Initial Notification to satisfy the requirements of 10 CFR 21.21(d)(3)(i) of a reportable defect that has been discovered at the Paducah Gaseous Diffusion Plant (PGDP). The defect is associated with 1 inch product cylinder valve packing nuts. The valves are manufactured by Hunt Valve Company, Inc., 1913 State Street, Salem, Ohio, 44460. Attached is the associated 10 CFR 21 evaluation checklist and a copy of pertinent problem reports. The Portsmouth Gaseous Diffusion Plant has also been apprised of this situation. Any question related to this subject should be directed to Mark Lombard at (301) 564-3248. Sincerely, James H. Miller Vice President, Production Attachment Page 17 of 18 10 CFR PART 21 EVALUATION CHECKLIST Page 1 of 2 Following questions provide the criteria for evaluation of 10 CFR Part 21 reportability: A.1 No Yes Has the NRC already been informed of this condition pursuant to 10 CFR 21 (for example, by a supplier? A.2 No Yes If yes, has USEC or LMUS been named as a recipient of the defective item? A.3 No Yes Has this condition already been reported to NRC in accordance with procedure UE2-MC-RE1030? If the answer to Questions A.1 and A.2 are "Yes", or the answer to Question A.3 is "Yes", the condition need not be reported under 10 CFR 21. Attach objective evidence of notification of the NRC and complete Part #. If the answers to Questions A.1, A.2, and A.3 are "No", continue with the evaluation. B.1 No Yes Is the identified condition a deviation or failure to comply associated with a basic component (including design, analysis, inspection, testing, fabrication, replacement parts, or consulting services)? If the answer to Question B.1 is "No", the condition is not reportable under 10 CFR 21; attach basis for conclusions and proceed to Section E. If the answer to Question B.1 is "Yes", continue the evaluation. No Yes If the answer to Question B.1 is "Yes", has the basic component been delivered to USEC/LMUS and accepted for use in the plant or an activity (includes USEC- dedicated commercial grade items)? If the answer to Question B.2 is "No", the condition is not reportable under 10 CFR 21; attach basis for conclusions and proceed to Section E. If the answer to Question B.2 is "Yes", condition is potentially reportable. Continue with the evaluation. C. Further, does the activity or basic component contain any of the following types of conditions? (Deviation means a departure from the technical requirements included in a procurement document.) No Yes 1) The installation, use, or operation of a basic component containing a deviation? No Yes 2) A condition or circumstance involving a basic component that could contribute to exceeding a safety limit as defined in the GDPs Technical Safety Requirements (TSRs)? No Yes 3) A failure to comply with any applicable regulation, order, or certificate issued by the NRC? If all of the answers in this section are "No", the condition is not reportable; attach basis for conclusion and proceed to Section E. If any answers are "Yes", continue with the evaluation. Page 18 of 18 Page 2 of 2 Could the deviation or failure to comply create a substantial safety hazard resulting in any of the following (assume there are no redundant or back-up system): No Yes 1) Exposure in exposure in excess of 10 CFR 20.1201 limits No Yes 2) Exposure of an individual in an unrestricted area to more than 0.5 rem in one calendar year (10 CFR 20.1301(c) No Yes 3) Release of radioactive material to an unrestricted area in excess of the limits in 10 CFR 20, Appendix B, Table 2 No Yes 4) A deficiency which seriously compromised the ability of a UF sub [illegible] confinement system to perform its designated function No Yes 5) Other (explain) If all answers in this section are "No", the condition is not reportable; complete Part E. If any answer is "Yes", condition is reportable. Continue with evaluation. E. Evaluation results and recommendation. Recommend condition be reported? No Yes If answer is "Yes", sign this part and continue to follow procedure UE2-EG-GE1039. Sign the evaluation checklist and forward to the Manager, NRA. If answer is "No", evaluation is complete. Sign the evaluation checklist and forward to Commitment Management for closure of Problem Report. Attach written summary of evaluation and basis for conclusions. Investigator Name Signature Date [illegible] Reviewer: Name Signature Date NRA: Name Signature Date 10 CFR PART 21 EVALUATION CHECKLIST Page 3 of 3 SUMMARY OF EVALUATION AND BASIS FOR CONCLUSIONS Cracking of the nuts has been observed and, in one case, resulted in a reportable release of UF sub 6. Metallurgical analysis of the cracked nuts has shown stress corrosion cracking to be the degradation mechanism. Intergrannular cracking has been detected in cylinder valve packing nuts which have been used in various stages of the enrichment process. In addition, intergrannular cracking of packing nuts has been detected in "new" cylinder valves removed from new cylinders to allow receipt inspections. The removed valves were placed in storage and were not exposed to plant process chemicals or handling practices affecting the packing nut. This indicates that the problem is a material or manufacturing problem with the nuts. Three valve packing nut materials are currently used; monel, ASTM B150 613 alloy, and CDA 636 alloy. The cracking problem has been observed only in the 636 alloy nuts on valves supplied by Hunt Valve Co., Inc.. USEC-651, Rev 7, Uranium Hexafloride, A Manual of Good Handling Practices, section 5.4.6, discusses past defects in one inch cylinder valves and the potential adverse effects. One past defect was packing nuts which have split during service. It is identified that this condition could allow the stem packing rings to be forcefully ejected from the valve, resulting in a UF sub 6 release. Failure of a cylinder valve packing nut and ejection of the valve packing with an open valve on a full cylinder would constitute a failure of a UF sub 6 confinement system. Business Prioritization System Page 1 Problem Report Response Sheet Response Due: / / ISSUE TITLE..: SMOKE RELEASED FROM CYLINDER VALVE ON PP-2549 ASSESSMENT...: PROBLEM REPORTS JANUARY - DECEMBER 1997 [UC97A0001] ISSUE ID.....: UC9710318 MANAGER.......: PENROD SR FINDING NO...: PR-CO-97-0289 FUNC, ORG.....: 12 - Operations STATUS.......: CANC GROUP.........: (Unassigned) TYPE.........: PR-Problem Report SUB-TYPE.....: NW - Notification ORIGINATING FUNC. ORG.....: 12-Operations ORIGINATING GROUP.........: 793 -UF6 Handling Shifts PRIORITY.....: 0 INITIATED BY..: 28539 LOCATION.....: DISCOVERY DATE: 01/19/1997 2200 BUILDING.....: C-310 MAIL STOP....: C-331 PROCEDURE/SPEC./DRAW..: ROOT CAUSE DETERMINATION TapRoot Code(s): FLAGS DESCRIPTION UPGRADED TO EVENT REPORT PAD-ER-1997-001 A small wisp of smoke was released from the cylinder valve on cylinder PP-2549. PGLD YE-75 over the [illegible] withdrawal position pigtail was actuated. The operators were in the process of evacuating/purging the pigtail on a full product cylinder. The wisp was observed after the pigtail was pressured above atmosphere. A noticeable crack circumvents the packing nut. The operators exited the area and donned additional PPE. The pigtail was purged using subatmospheric doubling purges and the cylinder valve confirmed closed. Cylinder was disconnected with no further incident and defective valve tag and caution tag was placed on the cylinder. HF and uranium samples were pulled with negative results. The ARP was followed and the PSS notified. ACTIONS TAKEN NONE RECOMMENDED ACTIONS Replace cylinder valve on PP-2549. Analyze failure of valve cap. PSS JUSTIFICATION/COMMENTS Urine samples were obtained. UF6 detection safety system was actuated and operated as designed. 24 hour event report PAD-1997-DD2 issued. Criteria met Appendix E [(a) unusual and Appendix F. J. (2) 24 hour. Small wisp released from cracked packing nut when pigtail pressured up. HP smears were negative. This PR should be evaluated for 10CFR21 reportability. REMARKS MANAGEMENT RESPONSE Business Prioritization System Page 1 Problem Report Response Sheet Response Due: 04/04/1997 ISSUE TITLE..: C-310 RELEASE FROM CYLINDER VALVE PR-591 ASSESSMENT...: PROBLEM REPORTS JANUARY - DECEMBER 1997 [UC97A0001] ISSUE ID.....: UC97I0699 MANAGER.......: PENROD SR FINDING NO...: PR-CO-97-0640 FUNC, ORG.....: 12 - Operations STATUS.......: PART GROUP.........: 070 Operations Management TYPE.........: PR-Problem Report SUB-TYPE.....: (Unassigned) ORIGINATING FUNC. ORG.....: 12-Operations ORIGINATING GROUP.........: 793 -UF6 Handling Shifts PRIORITY.....: 0 INITIATED BY..: 13945 LOCATION.....: DISCOVERY DATE: 02/07/1997 0827 BUILDING.....: C-320 MAIL STOP....: C-331 PROCEDURE/SPEC./DRAW..: CP4-CO-072010 Rev. 0 ROOT CAUSE DETERMINATION TapRoot Code(s): FLAGS DESCRIPTION A small wisp of smoke was released from the cylinder valve on cylinder PK-591 during purging operations. This activated PGLD YE-73 in the R3 withdraw position ventilation duct. The wisp was observed after the pigtail was pressured above atmosphere. A noticeable crack circumvents the packing nut. ACTIONS TAKEN Operations immediately exited the area. Alarm was responded to per procedure. HF samples and wipes were negative. The pigtail was purged using subatmospheric doubling purges. Cylinder was disconnected with no further incident. RECOMMENDED ACTIONS Replace cylinder valve on PK-591. Investigate failure of packing nut. PSS JUSTIFICATION/COMMENTS 24 Hour Event Report per UE2-MC-RE1030, Appendix E criteria 1. I, unusual (a), and Appendix F criteria J.2. Appropriate response was made. HF and HP surveys were negative. Precautionary urine samples were obtained from the two workers who were present. REMARKS 03/06/97: Per PRSC, assign to Operations for disposition. This PR will be closed to PR-CO-97-0640 which is a SCAQ. 03/05/97: DOE reportable events due to DOE on/after 03/03/97 (date NRC assumed regulatory oversight) have been downgraded to problem reports, PR-CO-97-0640 has been placed back in PART status and will be taken back to the screening Committee for SCAQ determination, action plan due date, etc. Event Report PAD-DR-1997-004D (UC9710810) has been cancelled. MANAGEMENT RESPONSE Business Prioritization System Page 1 Problem Report Response Sheet "31" PROBLEM REPORTS Response Due: 03/20/1997 ISSUE TITLE..: PACKING NUT ON CYLINDER PP-2520 IN E YARD CRACKED ASSESSMENT...: PROBLEM REPORTS JANUARY - DECEMBER 1997 [UC97A0001] ISSUE ID.....: UC9711002 MANAGER.......: BROWN JR FINDING NO...: PR-SU-97-08588 FUNC, ORG.....: 31 - Engineering STATUS.......: PART GROUP.........: 814-Mechanical & Process TYPE.........: PR-Problem Report SUB-TYPE.....: (Unassigned) ORIGINATING FUNC. ORG.....: 38-Production Support ORIGINATING GROUP.........: 340 -Process Technical & NDA PRIORITY.....: 0 INITIATED BY..: 32454 LOCATION.....: DISCOVERY DATE: 02/18/1997 1445 BUILDING.....: C-765-E MAIL STOP....: C-710 PROCEDURE/SPEC./DRAW..: ROOT CAUSE DETERMINATION TapRoot Code(s): FLAGS DESCRIPTION The packing nut on cylinder PP-2520 in the E yard was found cracked around the circumference (or approximately the top thread) through approximately 80% of the section. This is a "Hunt" valve alloy "6.36" nut. (or #390795-8). This packing nut failure was found while inspecting Paducah plant cylinders with an eddy current probe for indications of cracked nuts, but was clearly visible with crack opening of approximately 1/8". The cylinder appeared to be empty. ACTIONS TAKEN NONE RECOMMENDED ACTIONS NONE PSS JUSTIFICATION/COMMENTS Found during a random sampling of Hunt valves with the "6-36" packing nut. No sign of any leakage. 10 ton cylinder. Per NMC&A records, is an empty cylinder with notation requiring a valve change. This should be evaluated for 10 CFR 21 and 71.95 applicability. REMARKS 02/20/97: Part A is assigned to Operations and Management response provided at PRSC. No further action required. Part 5 is assigned to Engineering to evaluate for 10 CFR applicability. MANAGEMENT RESPONSE Name of person providing response: *** END OF DOCUMENT ***

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