United States Nuclear Regulatory Commission - Protecting People and the Environment


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:





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