ML20216E691
| ML20216E691 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 09/13/1999 |
| From: | Jonathan Brown UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-99-2051, NUDOCS 9909170020 | |
| Download: ML20216E691 (3) | |
Text
4 USEC A Global Energy Company L
September 13,1999 GDP 99-2051 i
l
.U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Portsmouth Gaseous Diffusion Plant (PORTS)
Docket No. 70-7002 Event Report 99-18 1
i Pursuant to Safety Analysis Report Section 6.9, Table 6.9-1, J(2), Enclosure 1 provides the required 30 day Event Report for an event that resulted from the actuation of a cascade automatic data processing smokehead in the X-333 building low assay withdrawal station at the Portsmouth Gaseous Diffusion Plant. Investigation activities are continuing to determine the root cause and appropriate corrective actions. This event report will be revised following completion of these activities. The expected date for submitting the revised report is November 13,1999. There are no commitments contained in this report.
Shbuld you require additional information regarding this event, please contact Scott Scholl at t
l (740) 897-2373.
Sincerely,
. Morris Brown General Manager Portsmouth Gaseous Diffusion Plant
Enclosures:
As Stated.
cc:
NRC Region 111 Office h'79 i
NRC Resident inspector - PORTS 9909170020 990913 PDR ADOCK 07007002 C
PDR 17)On0g United States Enrichment Corporation Portsmouth Gaseous DifTusion Plant P.O. Box 628, Piketon, OH 4566t L
4 GDP 99-2051 Page1of2 Event Report 99-18 Description of Event At 0518 hours0.006 days <br />0.144 hours <br />8.564815e-4 weeks <br />1.97099e-4 months <br /> on August 15,1999, Operations personnel responded to a cascade automatic data l
processing (CADP) system smokehead alarm at the X-333 Low Assay Withdrawal (LAW) compressor area. _ Smokchead SXE2783 alarmed shortly after changing the system from mode IV l
(standby) to mode 111 (withdrawal) as part of normal LAW operations. The responding operator l
observed smoke in the LAW compressor area, immediately evacuated the area and reported the i
outgassing. At 0526 hours0.00609 days <br />0.146 hours <br />8.69709e-4 weeks <br />2.00143e-4 months <br /> a building recall was initiated. The outleakage was stopped when the LAW station piping was vented below atmospheric pressure by the operator in the area control room.
The smokehead automatically reset at 0529 hours0.00612 days <br />0.147 hours <br />8.746693e-4 weeks <br />2.012845e-4 months <br />.
The emergency response organization responded and monitored air quality for hydrogen fluoride and airborne radioactivity and surveyed for transferrable surface contamination. All sample results were i
less than minimum detectable act,.
The LAW A/B compressor is an electric motor driven, direct drive, centrifugal, two stage Worthington compressor with a shaft seal. The smokehead actuation was determined to be a valid safety system actuation most likely caused by an outgassing of the compressor shaft seal. Safety system actuations are reportable in accordance with the Safety Analysis Report Section 6.9, Table 6.9-1, J(2).
Cause of Event l
The direct cause of the CADP actuation was a UF release from the LAW A/B compressor shaft seal 6
area. Operations personnel reviewed the LAW station data sheets to determine whether any adverse trends could be found leading up to this outgassing. The data showed the LAW A/B compressor seal exhaust control valve (CV) position and seal differential pressure readings were out of tolerance from August 5 to August 15,1999. The minimum / maximum values listed for seal exhaust CV position is 10%90% and 1.0-6.0 psi for seal exhaust differential pressure. The readings on August 15,1999, were 102% and.50 psi respectively. These readings could indicate an operational problem within the compressor seal system, such as a failed seal feed component, seal exhaust component, vent plugging, or a seal outside of normal operating parameters.
The analysis to determine the root cause of outgassing has not been completed. "reliminary results indicate that the outgassing may have occurred due to plugging of the vent hole in the Worthington compressor shaft. This could cause the pressure in the seal cavity to increase above atmospheric pressure. The actual failure mode can only be determined during compresso: disassembly which is currently scheduled for October 1999.
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4 GDP 99-2051 Page 2 of 2 Event Report 99-18
' A review of operating procedures for the extended range product station and Tails Withdrawal station found that compressors were to be evaluated and subsequently shut down when. seal parameters were out of tolerance. LAW procedures do not require actions such as shutdown or increased monitoring and do not provide guidance for operating a Worthington compressor with a seal outside of normal operating parameters. To address this difference, Cascade personnel were directed to vent the Worthington compressors in LAW to below atmospheric pressure whenever the seal instrumentation is outside normal operating parameters.
The results of the compressor disassembly and visual inspection will be used to determine the root cause and corrective actions necessary to correct the problem and prevent recurrence. This report will be revised when these actions are complete.
Corrective Actions Planned corrective ections will be provided with the revised event report.
Extent of Exposure ofIndividuals to Radiation or Radioactive Materials Two operations personnel submitted urine samples fo: urinalysis.' The bioassay results were less than 5 pg/l of uranium. The urinalysis program flag action level is 5 pg U/l as specified in SAR Table 5.3-4.
Lessons Learned l-
' Lessons Learned will be provided with the revised event report.
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