ML20249B198

Ack Receipt of Informing NRC of Steps Taken to Correct Violations Noted in Insp Rept 70-7001/98-06 on 980507

ML20249B198
Person / Time
Site:	Paducah Gaseous Diffusion Plant
Issue date:	06/16/1998
From:	Hiland P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	John Miller UNITED STATES ENRICHMENT CORP. (USEC)
References
70-7001-98-06, 70-7001-98-6, NUDOCS 9806220163
Download: ML20249B198 (1)

Text

. _ _ - _ - _ _ _ - _ - _ _ _

J June 16',.-1998

. Mr. J. H. Miller

Vice President-Production 7

Unded States Enrichment Corporation Two Democracy Center 6903 Rockledge Drive.

' Bethesda, MD 20817 '

SUBJECT:

RESPONSE TO INSPECTION REPORT 70-7001/98006

Dear Mr. Miller:

This refers to your June 8,1998, response to the Notice of Violation (NOV) transmit *ed to you by our letter dated May 7,1998, with inspection Report 70-7001/98006.. We have reviewed your response and corrective actions and have no further questions at this time. Your corrective

- actions will be examined during future inspections,

. If you have any questions, please contact me at (630) 829-9603.

Sincerely, Original Signed by-9906220163 990616 PDR ADOCK 07007001 Patrick L. Hiland, Chief C

PDR Fuel Cycle Branch w

Docket No. 70-7001 H. Pulley, Paducah General Manager cc' L; L. Jackson, Paducah Regulatory Affairs Manager J. M. Brown, Portsmouth General Managar

' S. A. Toolle, Manager, Nuclear Regulatory

' Assurance and Policy, USEC Paducah Resident inspector Office Portsmouth Resident inspector Office

/

R. M. DeVault, Regulatory Oversight Manager, DOE J. C. Hodges, Paducah Site Manager, DOE I

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Docket File PUBLHC IE-07 R. Pierson, NMSS P. Ting, NMSS.

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T CSEC A Global Energy Company June 8,1998 GDP 98-1039 U. S. Nuclear Regulatory Commission Attention: Document Control Desk

'. Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)

Docket No. 70-7001 Response to Inspection Report (IR) 70-7001/980d6 Notice of Violation (NOV)

The subject IR contained one NOV concerning the failure to verify by testing the adequacy of the

' Building C-720 criticality accident alarm system (CAAS) horn design under conditions that simulate the most adverse design requirements. USEC's response to the violation is provided in Enclosure

1. The corrective actions specified in the enclosures apply solely to PGDP. lists the conunitment contained in this submittal. Any questions regarding this matter

. should be directed to Larry Jackson at (502) 441-6796.

Sincerely, a

/

Steve Polston General Manager Paducah Gaseous Diffusion Plant i

Enclosures:

As Stated I

i cc:

NRC Region III Office 1

NRC Resident Inspector - PGDP

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l P.O. Box 1410, Paducah, KT 42001

'JUN 12 $

Telephone 502-441-5803 Fax 502-441-5801 http://www.usec.com

- O&es in Livermore, CA Paducah, KY Portsmouth,~ OH Washington, DC f)d si,i 7Ae m

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l GDP 98-1039 Page 1 of 3 UNITED STATES ENRICHMENT CORPORATION (USEC)

REPLY TO NOTICE OF VIOLATION (NOV) 70-7001/98006-01 Restatement of the Violation Title 10 of the Code of Federal Regulations, Part 76.93," Quality Assurance," requires, in part, that the Corporation shall establish and execute a Quality Assurance Program.

Item 3 of Section 2.3.3.4 of the Quality Assurance Program," Design Verification," required, in part, that procedures for design verification activities shall be established and that design verification shall be completed prior to relying upon the component, system, structure, or computer program to perform its function. Item 5 requires,in part, that verification by testing shall demonstrate adequacy of performance under conditions that simulate the most adverse design requirements.

Contrary to the above:

From March 3,1997 through April 6,1998, the Corporation failed to verify by testing the adequacy of the Building C-720 criticality accident alarm system horn design under conditions that simulate the most adverse design requirements prior to relying upon the system to perform its function of alerting personnel to an inadvertent criticality. Specifically, testing and quarterly surveillance tests conducted after the design was modified in March 1997 did not demonstrate that the 24-volt channel of the Building C-720 criticality accident alarm system would sound the building horns for the 120 seconds required by Technical Safety Requirement 2.6.4.1 upon loss of the 48-volt channel.

USEC Response L

Reason for the Violation The root cause for this violation was an inadequate understanding of the C-720 criticality accident alarm system (CAAS) circuit design resulting in an inadequate Post-Maintenance Test (PMT). As was noted in the Inspection Report, a modification was made to the CAAS horn circuitry on March 1,1997, in order to improve its response time. Plant personnel did

. not recognize that this modification might affect the capability of one of the two independent alarm circuits to sound the building horns until manually reset. (i.e., a design requirement).

As a result, the procedure used to test the CAAS circuitry following the modification (i.e.,

CP4-GP-IM6178, " Maintenance of the C-720 Criticality Accident Alarm System"), did not ensure that the alarm homs would sound for a minimum of 120 seconds using either of the two independent alarm circuits. The inadequate understanding of the circuit design is considered an isolated case, in that review of the vendor's product documentation and related discussions with the vendor did not identify any concerns with the proposed modification.

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GDP 98-1039 Page 2 of 2 l

II.

Corrective Actions Taken and Results Achieved

1. An additional modification of the circuitry was completed and the C-720 CAAS was satisfactorily tested by Maintenance on April 8,1998. This modification replaced a relay which had caused the horns to sound for only 10 seconds on the 24-volt circuit path.

2. The vendor technical manual was updated to include auditional information on the alarm input channels for the C-720 CAAS Audible Alarm System. This infonnation provided design information not previously available.

'3.

On May 21,1998, plant personnel verified that each of the two independent alarm circuits could independently maintain actuation of the CAAS horns for at least 120 seconds.

III.

' Corrective Action to Be Taken The lessons icained associated with this violation will be provided to appropriate design Engineering personnel by July 1,1998.

IV.

Date of Full Compliance USEC achieved full compliance on May 21,1998, when it was verified that the system could independently maintain actuation of the C-720 CAAS horns for at least 120 seconds.

i

6 GDP 98-1039 Page1ofI LIST OF COMMITMENTS 1.

The lessons learned associated with this violation will be provided to appropriate design Engineering personnel by July 1,1998.

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