ML20154G757
| ML20154G757 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 10/05/1998 |
| From: | Jonathan Brown UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-98-2044, NUDOCS 9810130296 | |
| Download: ML20154G757 (3) | |
Text
.
t y USEC
. A ciob.i so.rsy comp.,y October 5,1998 GDP 98-2044 i
United States Nuclear Regulatory Commission Attention: Document Control Desk -
Washington, DC 20555-001 Portsmouth Gaseous Diffusion Plant (PORTS)
Docket No. 70-7002 Event Report 98-13 Pursuant to the Safety Analysis Report Section 6.9, Table 6.9-1, J (2), Enclosure 1 provides the 30-day Event Report for an event that resulted from the actuation of CADP smokeheads in the X-333 Process Building due to an unplanned release of UF. Investigation activities are 6
continuing to determine the root cause and corrective actions for this event. This report will be revised following completion of these activities. The revised report is scheduled for December 10,1998. There are no new commitments contained in the report.
Should you require additional information regarding this event, please contact Scott Scholl at l
(740) 897-2373.
i Sincerely,
) / V(n d
. Morris Brown h
General Manager
. Portsmouth Gaseous Diffusion Plant l
Enclosures:
As Stated
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NRC Region III Office NRC Resident Inspector - PORTS 9810130296 981005 7 PDR ADOCK 07007002' C
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PO. Box 800, Portsmouth, OH 45661 Telephone 740-897-2255 Fax 740-897-2644 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth, OH Washington. DC
GDP 98-2044 Page 1 of 2 Event Report 98-13 Description of Event At 0848 hours0.00981 days <br />0.236 hours <br />0.0014 weeks <br />3.22664e-4 months <br /> on September 6,1998, a process operator reported to the Area Control Room an observation of smoke in Unit 33-3. At 0850 hours0.00984 days <br />0.236 hours <br />0.00141 weeks <br />3.23425e-4 months <br />, CADP smokehead S-31, which provides coverage for cell 33-3-3 stage 1 and 2, actuated. At 0853 hours0.00987 days <br />0.237 hours <br />0.00141 weeks <br />3.245665e-4 months <br />, the ACR-1 personnel implemented "See and Flee" measures by sounding the building recall horns.
At 0857 hours0.00992 days <br />0.238 hours <br />0.00142 weeks <br />3.260885e-4 months <br />, Fire Department personnel arrived at X-333 and entered the building wearing required personal protective equipment. Personnel monitoring the area determined smoke was coming from the X-33-3-3 stage 1 compressor seal. At 0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br />, cell 33-3-3 was taken off-i stream and the cell pressure was reduced below atmospheric. At 0959 hours0.0111 days <br />0.266 hours <br />0.00159 weeks <br />3.648995e-4 months <br />, cell 33-3-3 motors were shut down due to compressor surging caused by air inleakage. At 1145 hours0.0133 days <br />0.318 hours <br />0.00189 weeks <br />4.356725e-4 months <br />, an "All Clear" was granted.
According to the Technical Safety Requirements for the Portsmouth Gaseous Diffusion Plant, the CADP smoke detectors are required to be operable when a cell is operating above atmospheric l
pressure. In this instance, cell 33-3-3 B-line pressure was above atmospheric, which would make the actuation of this smoke detector alarm reportable in accordance with the Safety Analysis Report, Section 6.9, Table 6.9-1, J (2).
The material that outgassed was low-enriched UF at approximately 0.92% U-235.
6 Cause of Event The direct cause of the CADP actuation was a UF release from the cell 33-3-3 stage IB 6
compressor seal. The stage IB seal was installed on October 25,1997, and cell 33-3-3 was placed in service on December 24,1997. During the preparation to place the cell on-stream, personnel determined the stage 1B seal was allowing ambient air to leak through the atmospheric side of the seal and into the seal cavity. In accordance with procedure XP4-CO-CA2125, " Cell Compressor Seal Operation in X-333", the seal feed and seal exhaust were valved off and a 1 psig seal air pressure applied to the atmospheric gland to prevent wet air inleakage and to allow the "B" seal j
system to remain in control. When a seal is valved off, the seal feed is no longer applied to the j
seal cavity. The seal cavity pressure will remain at subatmospheric pressure via the vented cavity j
line. A UF outgassing can occur on a seal, whether valved in or valved off, when the vented I
cavity line is obstructed or the labyrinth fails to perform its designed function. When a leak occurred in the process gas side of the seal, UF filled the seal cavity and leaked out through the 6
atmospheric side of the seal.
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l GDP 98-2044 Page 2 of 2 i
Event Report 98-13 Cell 33-3-3 operated at below atmospheric pressure from December 24,1997, to approximately l
September 3,1998. The cell pressure rose above atmospheric pressure on September 3,1998, as a result of a planned cascade power load increase. Cell 33-3-3 operated above atmospheric pressure until September 6,1998, when the seal failure caused the cell to be taken off-stream.
An inspection of the seal following this event deter.nined that the gap between the compressor l
shaft and the seal labyrinth was greater than specification, and the compressor shaft had been l
worn. Investigation etivities to determine the causes and corrective action for this event are on-gomg. This event rerort will be revised following completion of these activities.
Corrective Actions i
Corrective e.ctions will be provided following completion of investigation activities.
l Extent of Exposure of Individuals to Radiation or Radioactive Materials There were no significant exposures to individuals from this incident to radiation or radioactive materials. Two operators who saw the outgassing submitted urine samples for analysis. The bioassay results were less than the minimum detectable amount. Based on the urine sample results, intakes were less than 1 ug of uranium. The limit for occupational workers is 10,000 ug of soluble uranium per week.
Lessons Learned l
Lessons learned will be provided following completion of investigation activities.
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