ML20211N092
| ML20211N092 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 10/10/1997 |
| From: | Allen D UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-2023, NUDOCS 9710160018 | |
| Download: ML20211N092 (3) | |
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United St:t:s Enrichment Corporation
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? Democracy Center 6903 Rockledge Drive Bethesda, MD 20817 Tel (301)564 3200
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l'niini %ies finielunent (hoponisjon October 10,1997 ODP 2023 United States Nuclear Rt aory Commission Attention: Document Control Desk Washington, D.C. 20555 0001 Portsmouth Ganous Diffusion Plant (PORTS) Docket No. 70-7002 Event Report 97-17 Pursuant to the Safety Analysis Report (SAR), Section 6.9, Table 6.91, J (2), Enclosure 1 provides the required 30 day written Event Report for an occurrence involving an actuation of the Cascade Automatic Data Processing (CADP) Smoke Detection System in the X-333 Building at the Portsmouth Gaseous Diffusion Plant.
Should you require additional information regarding this event, please contret Scott Scholl at 1
(614) 897-2373.
Sincerely,
'\\W Dale Al General Manager Portsmouth Gaseous Diffusion Plant DIA:SScholl:cw l
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NRC Region til D. Ilartland, NRC Resident inspector, PORTS ll i
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E E xlosure 1 h ;e'l of 2 Event Report 97-17 Description of Event i
On September 13,1997, at approximately 0812 hours0.0094 days <br />0.226 hours <br />0.00134 weeks <br />3.08966e-4 months <br />, the Cascade Automatic Data Processing (CADP) smoke detectors S-68 and S-85, which monitor the "B" bypass line between Cells 33-1-6 and 331-8, alarmed in the X-333 Process Building Area Control Poom #1. Following the alarm, operating personnel investigating the alarm observed smoke in the area where the smoke detector g
hends were located, near column G-10. At the time the smoke detectors alarmed, the pressure inside the bypass line was aoove atmospheric pressure (14.45 psia). Operations personnel in the area followed the "See & Flee" policy and evacuated the atfected area.
Building " recall" was sounded at 0820 hours0.00949 days <br />0.228 hours <br />0.00136 weeks <br />3.1201e-4 months <br /> and the Fire Department and Plant Shif1 Superintendent (PSS) were notified. At 0823 hours0.00953 days <br />0.229 hours <br />0.00136 weeks <br />3.131515e-4 months <br />, the PSS made an emergency response to the X-333 Process g
Building. At 0839 hoars, the emergency re> pond:rs, using Self Contained Breathing Apparatus and dressed in appropriate Personal Protective Equipment (PPE), entered the cell floor. The emergency responders sampled for airborne radioactivity. Samples were below detection levels.
At 1040 hours0.012 days <br />0.289 hours <br />0.00172 weeks <br />3.9572e-4 months <br />, operations personnel wearing PPE discovered a yellow / green dusting on an abandoned 1/4 inch instrument line, which was an indication on an outgassing of UF. Closer 6
inspection of the instrument line confirmed that there was a crimp in the line and that UF had 6
escaped through a crack in the line where the line was crimped. The instrument line was located inside the cell housing covering tl.e 30 inch "B" bypass line between Cells 33-1-6 and 33-1-8, near column G-10, where the stooke was observed catlier.
The :ikelihood of instrument line leaks has been assessed in the SAR (Section 4.1.1.3.1) which states,"Small amounts of UF and other toxic materials such as HF, ClF and UO F can be released 6
3 2 2 during samphng operations, seal changes, failure to obtain sufficient cell and piping UF negatives, 6
ruptured copper tubing, and possib'y through bufTer systems. These releases are prevented primarily by using engineering and adminis*.cafve controls. To protect the operator in the unlikely event a release does occur, operating specificatione require that perse mel performing operations and maintenance, where the possibility of release exist, wear protective equipment such as an individually fitted gas mask. Releases in these cases may mean that a few grams of UF will escape 6
to tiu vmosphere. There are no TSR systems (Safety Systems) to prevent the release of UF while perfe ting these types of operations. Engineering and adminisaative controls are concidered adequate."
According to the Safety Analysis Report (SAR1 for the Portsmouth Gaseous Diffusion Plant, the CADP smoke detectors are part of the UF detection alarm system and are classified as Q safety 6
systems when monitoring egipment operating above atmaspheric pressure. In this instance, the monitored equipment ("B" bypass line) was operating slightly above atmosphere. A CADP smoke
Docket No. 70-7002
- Page'2 of 2 Event Report 97-17 detector actuation is reportable in accordance with SAR, Section 6.9 Table 6.91, J (2).
Operation personnd received two previous smoke alarms on detectors S-68 and S-85 on September p(
12,1997. At 2020 hours0.0234 days <br />0.561 hours <br />0.00334 weeks <br />7.6861e-4 months <br /> and at 2205 hours0.0255 days <br />0.613 hours <br />0.00365 weeks <br />8.390025e-4 months <br /> respectively, the smokeheads activated and operators responded to both alarms. Smoke was witnessed near column G-10 following the first alarm.
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Following the first alarm a building " recall" was sounded and the Fire Department and PSS were 6--
notified and responded. Air samples taken following the alarm were below detection levels. The PSS determined that the smoke observed followir.g the first alarm was from a non-radiological source and no smoke was witnessed following the second alarm. As a result thue actuations were determined to be false alarms because no evidence of an outgassing was discovered.
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Cause of Event L
The direct cause of the CADP UF Smeku Detection System actuation was an outgassing of UF.
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The origin of the UF release was from a break in an abandor.ed and capped-off 1/4 inch instrument 6
line. One end of the instrument line tapped into the 30 inch "B" bypass line and the other end of the insument line was capped-off. The location of the break was approximately 6 ft. from where the 1/4 inch line tapped into the "B" bypass line.
The root cause of the instrument line break was a crimp in the tubing, v hich created a stress point in the line that eventually resulted in a crack in the tubing. The exact cause of the crimp was not determined. However, it probably occurred several years ago when the line was removed from service. The copper tubing was thought to have been previously used as an equalization line or for instrumentation that had been abandoned.
Corrective Actions 1.
On September 13,1997, n.aintenance persor. al, wearing PPE, pinched off the instrument line with a pinch-off tool.
Extent of Exposure ofIndividuals to Radiation or Radioactive Materials r-One individual was required to submit a urine sample as a result of the outgassing. The results were below 5 ug/ liter for soluble uranium (flag level). The calculated intake was 0.24 micrograms of uranium. The limit for occupational workers is 10,000 micrograms of uranium.
Lessons Learned There were no lessons learned from this event.
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