United States Nuclear Regulatory Commission - Protecting People and the Environment


ACCESSION #: 9707280078



                                                  United States

                                                  Enrichment Corporation



                                                  2 Democracy Center

                                                  6903 Rockledge Drive

                                                  Bethesda, MD 20817



USEC                                              Tel: (301) 564-3200

                                                  Fax: (301) 564-3201

United States

Enrichment Corporation



GEORGE P.  RIFAKES                                Dir: (301) 564-3301

EXECUTIVE VICE PRESIDENT, OPERATIONS              Fax: (301) 571-8279



                              July 24, 1997



                                             SERIAL: GDP 97-0117



U.S.  Nuclear Regulatory Commission

Attention: Document Control Desk

Washington, D.C. 20555-0001



Portsmouth Gaseous Diffusion Plant (PORTS)

Docket No. 70-7002

Written Notification of 10 CFR 21 Report



     The purpose of this letter is to provide written notification to the

Nuclear Regulatory Commission (NRC) in accordance with 10 CFR 21.21

(d)(3)(ii) of a reportable defect that has been identified at the

Portsmouth Gaseous Diffusion Plant (PORTS).  The Initial Notification of

this defect was provided to the NRC by USEC letter GDP 97-0106, dated

June 24, 1997.  The defect is associated with Release 21.1 of the STAAD-

III structural analysis program supplied by Research Engineers, Inc.,

22700 Savi Ranch, Yorba Linda, California, 92887-4608.  This program is

being used to evaluate the existing crane support structure at the X-326

ERP Withdrawal Station as part of an ongoing project to replace the

existing liquid UF sub 6 handling crane at this location.



     A defect was identified in Release 21.1 of the STAAD-III program

which yielded non-conservative results.  The nature of the defect was an

error in one of the load specifications in Revision 21.1 that does not

recognize a concentrated member load when it is applied to the weak axis

of a member using a global direction specification.  This defect could

have created, or contributed to, a substantial safety hazard.  Non-

conservative design of the crane support structure could increase the

potential for dropping a cylinder containing liquid UF sub 6.  The defect

was identified on April 25, 1997, during a review of STAAD-III output

calculations.



     Release 21.1 of STAAD-III was received by PORTS in May of 1996, and

had been used in nine design applications at PORTS besides the crane

design discussed above.  A review of each of these designs indicated that

none of them involved the load specification which exhibited the software

defect.  Therefore, these other applications are not affected by this

defect.



      Offices in Paducah, Kentucky Portsmouth, Ohio Washington, DC



U.S. Nuclear Regulatory Commission

Attn: Document Control Desk

July 24, 1997

GDP 97-0117, Page 2



     The defect described above does not appear to exist in STAAD-III,

Releases 20 and 22 as determined by tests performed at PORTS (Release 20

had been used in previous design applications and Release 22 is being

used currently).  Release 21.1 was not used to complete the crane support

structure design and has not been used on any other application since the

defect was discovered.  No further corrective action is required to

resolve this issue.



     The Paducah Gaseous Diffusion Plant has been apprised of this

     situation.



     No new commitments are made in this letter.  Any questions related

to this subject should be directed to Mark Lombard at (301) 564-3248.



                                   Sincerely,



                                   George P. Rifakes

                                   Executive Vice President, Operations



cc:  NRC Region III Office

     NRC Resident Inspector - PGDP

     NRC Resident Inspector - PORTS



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