ML20211H625
| ML20211H625 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 10/01/1997 |
| From: | Allen D UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-97-2021, NUDOCS 9710070014 | |
| Download: ML20211H625 (3) | |
Text
e United St:t:s Enrichment Corpor; tion 1
2 Domocracy Center i
6903 Rockledge Drive
(
Dethesda, MD 20817 Tel. (3011564 3200 Oliitnl$ ales I'mieliment Giapinition October 1,1997 GDP-97 2021 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555-001 Portsmouth Gaseous Diffusion Plant (PORTS)- Docket No. 70 7002 Event Report 97-16 Pursuant to the Safety Analysis Report (SAR), Section 6.9, Table 6.9-1, J (2), Enclosure 1 is the required 30 day written Event Report for an occurrence involving the actuation of the autoclave shell steam high pressure shutdown safety system in the X-342A Huilding at the Portsmouth Gaseous Di!Tusion Plant.
Should you require additional information regarding this event, please contact Scott Scholl at (614) 897 2373.
Sincerely, S&
llf )
Dale Allen General Manager j/
Portsmouth Gaseous Diffusion Plant DIA:SScholl:kpb 0}
ff Enclosures '
cc:
D. Ilartland, NRC Resident inspector, PORTS NRC Region 111 -
CW lillll101lll!!U11lll 9710070014 971001 PDR ADOCK 07007002 C
PDR _
Offices in Paducah, Kentucky Portsmov'h, Ohio Washington, DC
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' Docket No. 70-7002 -
Page1of2 Event Report 97-16
' Description of Event i On September 2; 1997, ~at 1345 hours0.0156 days <br />0.374 hours <br />0.00222 weeks <br />5.117725e-4 months <br />, X 342A Feed Vaporization and Fluorine Generation Facility autoclave #2 was in Mode II, heating a 48 inch Uranlem licxafluoride (UF ) cylinder when an p
audible and visual alarm foi steam shutdown was received.' Operators responding to the alarm '
found that the autoclave shell high steam pressure shutdown (ASliSPS' had actuated; The intemal autoclave pressure observed by the operators was 22.0 psia. TSR 2.1Ja.. lists the limiting control -
setting (LCS) for' ASilSPS as 8.0 psig (22.45 psla).
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- Autoclave #2 was immediately shutdown and declared inoperable at 1345 hours0.0156 days <br />0.374 hours <br />0.00222 weeks <br />5.117725e-4 months <br />. There was no
! release of hazardous matedal or radiological exposures associated with this event. The actuation of '
,c
- the AS11SPS safety system is_ reportable in accordance with the Safety Analysis Report (SAR),=
- Section 6.9, Table 6.91, J (2).
The ASilSPS is provided to ensure that a cylinder is not overheated due to an instrument or steam supply system failure, which could create a high cylinder pressurc ' situation leading to an UF. -
release Safety systems in addition to the. AS11SPS.which prevent the cylinder high temperature Esafety limit from being mached include the autoclave shell high pmssure containment shutdown and the UF. cylinder high temperature autoclave steam shutoff.:
Cause of Event w c.The steam shutdown was determined to be caused by an actuation of the AS11SPS due to higher than -
9 inormal steam pressure inside the autoclave shell.
- The root ca.ise of the' ASIISPS actuation on autoclave #2 was a failure of the steam pressure (regulator for the autoclave (Fisher steam regulator, model 92P). The component failed in the open.
' position and lost the ability to regulate the steam from the 50 psig steam header. The safety system
' operated as designed and shutdown the autoclave steam supply block valve at the proper setpoint.
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Docket No. 70 7002 Page 2 0f 2 Event Report 9716 The autoclave steam regulator is outside the Q boundary and is not a safety system component. A' review of system history and the problem report database for the past two years reveals that there -
have been no previous autoclave steam regulator failures in that period. No adverse maintenance -
or operational trends involving the steam regulators were identified.
There is no preventative maintenance on this component and the existing valve has been installed for many years. This component is scheduled to be replaced with an improved regulator as part of L
the autoclave steam supply and condensate removal system upgrades identified in the Compliance Plan, Issue 3.
L Autoclave #2 was declared inoperable pending replacement of the steam regulator. Since no adverse trends relating to the regulators were identified, there were no further corrective actions required.
Corrective Actions The failure of the steam regulator was de:ennined to be an isolated occurrence. - As a result, no further corrective actions are required.
Extent of Exposure ofIndividuals to Radi.6 tion or Radioactive Materials There were no exposures to individuals from this incident to radiation or radioactive materials.
Lessons Learned The steam regulator can fall in the open position and cause an ASilSPS actuation. Although the steam regulator failure in this event was determined to be an isolated occurrence, any future regulator failures will be evaluated to determine whether an adverse trend is developing.
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