ML20217F956
| ML20217F956 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 09/29/1997 |
| From: | Toelle S UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Pierson R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GDP-97-0146, GDP-97-146, NUDOCS 9710090113 | |
| Download: ML20217F956 (4) | |
Text
United Stat:s Enrichm;nt Corporation 2 Democracy Conter 6903 Rockledge Drive Bethesda, MD 20817 Tel (301)564 3000 Fax (301) S64-3201 friited S.ites flitirhtnent Girlioration September 29,1997 Mr. Robed C. Pierson SERIAL: GDP 97-0146 Chief, Special Projects Branch Division of Fuel Cycle Safety and Safeguards, NMSS United States Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Docket No. 70-7001 Modification of the Autoclave Interlock Controls-Compliance Plan Issue 3, Action 8.
Dear Mr. Pierson:
Compliance Plan issue 3, Action 8, Autoclave Upgrades, requires modification of the C-360 autoclave controls to prevent the autoclaves from being inadvertently opened when an autoclave fligh Pressure Isolation System containment signal is present. USEC has reviewed the existing facility design for the C-360 autoclaves and has determined that the existing autoclave hydraulic system design will prevent the autoclaves from being opened in the event that a fligh Pressure Isolation System containment i
signal is present, Therefore, the existing system installation performs this function and PGDP is currently in compliance with this required action.
The autoclave controls design logic is identical for all four autoclaves m C-360. Autoclave No. I will be described here for illustration. Upon a high-high pressure trip (High Pressure isolation System containment signal), control relays CR-141 A and CR-141R are de-energized. When either of these relays is de-energized. the control relay for the autoclave opening system, CR-111 A, is de-energized, which precludes autoclave hydraulics operation. Therefore, the existing autoclave controls design prevents the autoclaves from being opened in the e'.ent that a High Pressure Isolation System containment signal is present. The autoclave controls design logic is shown on Electrical Control Schematics E5E-15783-02 and E5E-14443-027, E5E-15783-04 and E5E-14443-028, E5E-15783-05 and E5E-14443-029, and E5E-15783-06 and E5E-14443-030 for Autoclaves 1,2,3 and 4, respectively. These drawings are available for review at PGDP.
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3 Offices in Paducah. Kentucky Portsmouth. Ohio Washington, DC
Mr. Robert C. Pierson
' September 29,1997 GDP 97-0146 Page 2 A functional teat, as required by TSR surveillance requirement SR 2.1.3.1-6, is conducted on a quarterly basis which verifies operability of the interlock preven, the autoclaves from opening on high pressure.
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The description of the !!igh Pressure Isolation System in SAR Section 3.6.7.5 will require a change to reflect that the liigh Pressure Isolation System dist.bles the hydraulic system required to open the autoclave shell, thus preventing the autoclave from being opened until the alarm condition has been cleared. The portion of SAR Section 3.6.7.5 requiring revision is also contained in the Commitment section of Capliance Plan, Issue 3. Therefore, the Commitment section of the Compliance Plan, Issue 3 also requires revision. USEC proposes to revise SAR Section 3.6.7.5 and the Commitment Section i
of Compliance Plan, Issue 3, as follcws:
"The autoclave high pressure isolation system causes the autoclave to go into the containment mode and sound an alarm if the internal pressure of the autoclave reaches 15 psig. In addition, the system disables the hydraulic system required to open the autoclave shell preventing the autoclave from opening until the alarm condition has been cleared. This system is identified as a system required to be included in the TSR."
In accordance with Reference 1 USEC requests NRC's acknowledgment of this proposed change to the Commitment section of the PGDP Compliance Plan, Issue 3. Within 30 days of receipt of the NRC staffs acknowledgment of this proposed change, USEC will revise the above noted Compliance Plan issue and SAR sections accordingly.
Should you have any_ questions related to this subject, please contact Mark Smith at (301) 564 3244.
Commitments contained within this letter are noted in Enclosure 1.
Sincerely,
/t S. 9.
ll Steven A.Toelle Nuclear Regulatory Assurance and Policy Manager ce:
NRC Region 111 Office NRC Resident Inspector-PGDP NRC Resident Inspector-PORTS
/
Mr. Robert C. Pierson
' September 29,1997 GDP 97-0146 Page 3 References
- 1. NRC Letter, Robert C. Pierson to Mr. Robert L. Woolle), " Requirements for Changes to the Compliance Plans", dated July 15,1997.
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I linclo;ure 1 GDP 97 0146 Page1ofI List of Commitments
- 1. Within 30 days of receipt of the NI(C staffs acknowledgment of the proposed change to the
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" Commitment" section of the PODP Compliance Plan, Isaue 3, addressing the lockout of the l
autoclave hydraulles upon actuation of the autoclave high pressure isolation system (Issue 3, item 8), US!!C will revise the above noted Compliance Plan issue and SAR sections.
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