ML20237B489
| ML20237B489 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 08/11/1998 |
| From: | Toelle S UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Paperiello C NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GDP-98-0161, GDP-98-161, NUDOCS 9808180334 | |
| Download: ML20237B489 (4) | |
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.USEC A ciob.: sn rsy comp.ny August 11,1998 ODP 98-0161 Dr. Carl J. Paperiello Director, Office of Nuclear Material Safety and Safeguards Attention: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusiott Plant (PGDP)
Docket No. 70-7001 Compliance Plan Issue 44, Operational / Safety System Trip Redundancy
Dear Dr. Knapp:
Issue 44 of the Plan for Achieving Compliance With NRC Regulations at the Paducah Gaseous
' Diffusion Plant (Compliance Plan) contains a required action that states:
"A review of system designs will be performed where operational trips and alarms 1
coincide with the set points for safety system actuation based on the same monitored parameter and the same equipment actuated. Where redundant operational and safety system actuations exist, corrective action will be identified that may include justification either for the redundancy or system modifications to eliminate the redundancy. The results of this review will be submitted to the NRC for review and
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approval by December 31,1997. If the review determines that a system modification is required, this Compliance Plan issue will be revised to establish a new completion date for compliance."
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On December 31,1997, USEC transmitted the results of this review to the NRC (Reference.1). In l
this submittal, USEC identified an operational trip for the Freezer / Sublimer Iligh-Iligh Weight Trip l
that is designed to actuate at a value below the safety-related control setting. Therefore, USEC informed NRC that we planned to submit a Certificate Amendment Request (CAR) to revise this i
Compliance Plan Issue to establish a corapletion date for the removal of this trip. Subsequently, a draft CAR was submitted to DOE for review and approval on January 30,1998 (Reference 2). DOE i
indicated their concurrence with this proposed revision on February 17,1998 (Reference 3).
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USEC has further evaluated this issue and has decided to rescind this proposed modification. The l-freezer /sublimers have both a hard-wired safety system Ifigh-Iligh Weight Trip (TSR 2.4.3.1.) and a computerized (DPCS)lligh-liigh Weight Trip. The PGDP Safety Analysis Report (S AR) describes f
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Dr. Carl J. Paperiello
- ' ugust 11,1998 A
GDP 98-0161, Page 2 both of these trip features (SAR sections 3.3.4.7.3 and 4.3.2.3.4). Specifically, the DPCS provides for semi-automatic control of the freezer /sublimers based on operator input by controlling the rate of UF6 transfer and by transferring the fre:zer/ sublimer to the cold standby mode when the specified
' net UF6 weight is achieved. The DPCS also provides for a High-High Weight Trip which is set -
approximately 10 percent below the safety system High-Iligh Weight Trip. The High-High Weight Trip safety system is hard-wired and acts independently from the DPCS to place the freezer / sublimer
. into modified hot standby when the limiting control setting in TSR 2.4.3.1 is reached.
In lieu of removing the operational trip for the Freezer / Sublimer High-High Weight Trip, USEC will report actuations of this operational trip as if they were safety system actuations, as is now currently
- required by the Justification for Continued Operation (JCO) for this Compliance Plan Issue. Because there have not been any actuations of this operational trip since this system was installed, over four years ago, USEC believes this approach will not result in any'significant increase in event reports.
l USEC will revise the affected procedure, by October 30,1998, to require reporting of the operational i
trip for the Freezer / Sublimer DPCS High-High Weight Trip as a safety system actuation. If, at some time in the future, USEC wishes to delete this operational trip, the modification will be performed
' in accordance with the requirements of 10 CFR 76.68. lists the commitment contained in this letter. If you have any questions or require additional information, please contact Larry Jackson at (502) 441-6796.
Sincerely, i
S. A.
I Steven A.Toelle Nuclear Regulatory Assurance and Policy Manager i
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Dr. Car,1 J. Paperiello
' Aug st 11,1998 ~
GDP 98-0161, Page 3
References:
1.
Letter from Steven A. Toclle (USEC) to Robert C. Pierson _(NRC),
" Compliance Plan Issue 44, Operational /Safbty System Trip Redundancy,"
Letter GDP 97-0226, December 31,1997.
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2.
Letter from Steven A. Toelle (USEC) to Randall M. Devault (DOE),
" Department of Energy (DOE) Review and Approval of Change to Compliance Plan Issue 44 (PGDP)," Letter No. DOE 98-0005, January 30, 1998.
3.
Letter from Randall M. DeVault (DOE) to Steven A. Toelle (USEC),
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" Department of Energy (DOE) Review of Change to Compliance Plan Issue 44 Operational / Safety System Trip Redundancy," dated February 17,1998.
Enclosure:
As Stated cc: _ NRC Region III Office NRC Resident Ir.spector - PGDP NRC Project Manager - PGDP Mr. Randall M. DeVault (DOE) l L
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I Enclosure !
GDP 98 0161 f
Page1ofI l
List of Commitments
- USEC will revise the afrected procedure, by October 30,1998, to require reporting of the operational trip for the Freezer / Sublimer DPCS High-High Weight Trip as a safety system actuation.
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- Regulatory commitments contained in this document are listed here. Other corrective actions listed in this submittal are not considered regulatory commitments in that they are either statements of actions completed, or they are considered enhancements to USEC's investigation, procedures, programs, or operations.
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