ML20206C898
| ML20206C898 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant |
| Issue date: | 04/26/1999 |
| From: | Jonathan Brown UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-99-2019, NUDOCS 9905030241 | |
| Download: ML20206C898 (6) | |
Text
.
YUSEC
\\ A ciob.: energy company April 26,1999 GDP 99-2019 i
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 99-05 Pursuant to 10CFR 76.120(d)(2), Enclosure 1 provides a revised 30-day written Event Report for an event involving an actuation of the Cascade Automatic Data Processing (CADP) Smoke Detection System in the X-330 Building at the Portsmouth Gaseous Diffusion Plant. Enclosure 2 is a list of commitments made in the report.
Should you require additional information regarding this event, please contact Scott Scholl at (740) 897-2373.
Sincerely,
/flr$;1 %
. Morris Brown General Manager Portsmouth Gaseous Diffusion Plant j
Enclosures:
As Stated
[
cc:
NRC Region Ill Office NRC Resident Inspectors - PORTS YS 9905030241 990426 I
PDR ADOCK 07007002 :
C PDR
\\
b t.O P.O. Box 800, Portsmouth, OH 45661 Telephone 614-897-2255 Fax 614-897-2644 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth. OH Washington, DC
GDP 99-2019 Page 1 of 4 Event Report 99-05 Description of Event At approximately 1003 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.816415e-4 months <br /> on March 25,1999, the Cascade Automatic Data Processing (CADP) smoke detectors S33 and S34, which monitor Cell 31-3-3, alarmed in the X-330 Process Building i
Area Control Room #2. A Front Line Manager (FLM) who was on the cell floor at the time observed a light haze above the cell housing of Cell 31-3-3. At the time of the alarm, the cell was being charged with UF in preparation for placing the cell on stream. The cell pressure was 6
approximately 18 psia when the alarm occurred. Operations personnel in the area followed the "See
& Flee" policy and evacuated the affected area. The cell was immediately shutdown, which lowered the pressure to sub-atmospheric and stopped the leak. Emergency personnel responded but did not observe any smoke when they arrived at the scene.
According to the Safety Analysis report (SAR) 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 equipment operating above atmospheric pressure. In this instance, the monitored equipment (Cell 31-3-3) was operating above atmospheric pressure. This CADP smoke detector actuation is reportable in accordance with SAR, Section 6.9 Table 6.9-1, J(2).
Cause of Event The direct cause for the CADP actuation was a UF. release from a crack in a quarter inch diameter copper instrument line. The copper line is part of the Blow Out Preventer (BOP) purge line located on the "B" stream side of the stage 8 compressor.
The root cause for the cracked BOP purge line was that the design of the X-31 size compressors
. requires that maintenance activities in the motor side compressor seal area be performed under cramped conditions. These conditions cause the copper lines in the immediate vicinity of the seal area to be susceptible to damage during maintenance activities. At the time of this event, Cell 31-3-3 was being retumed to service following replacement of the compressor seal, load bearing and BOP
- actuator, which are located on the motor side of the compressor. Since the cell was running above atmospheric pressure, with no leakage to atmosphere prior to shutdown for the above componeni replacements, it appears likely that the copper BOP purge line was damaged as a result of this maintenance activity.
Interviews with maintenance personnel were conducted to detennine whether compressor seal, load bearing or BOP actuator replacement could result in contact with the instrument lines in the seal area. Personnel indicated that only compressor seal and BOP actuator replacement would likely result in contact with these lines. The procedures used for compressor seal and BOP replacement
GDP 99-2019 Page 2 of 4 Event Report 99-05 were then reviewed to determine if adequate guidance existed for preventing damage to instrument lines and to determine what PMT requirements e :ist to detect instrument lines which may have been damaged.
Procedure XP4-OM-MM4501 " Compressor BOP Actuator Removal and Installation" was reviewed.
The procedure contains a caution statement indicating that the BOP wrench can damage the BOP actuator purge line while installing an actuator. The PMT form for the BOP actuator replacement (A-4927/PMT-ME-1998-0143, Rev 0) directs operators to XP4-CO-CN2131 A, " BOP Operations",
Section 8.5 for PMT requirements. Section 8.5, which was the section used to test the 8B BOP actuator on March 21,1999, lists the actions needed to soap test the BOP actuator. This section does not include soap bubble testing of the adjacent instrument lines.
Procedure XP4-OM-MM4202, "29 and 31 Type Compressor Seal Changes" was also reviewed. The procedure does not contain instructions for maintenance personnel working in the seal area to use caution when working around instrument lines. The PMT form for the seal replacement I
(PMT-ME-1998-0102, Rev.1) does include the requirement to pressurize the seal cavity and soap bubble test the seal cover, bolts and instrument lines, but does not define the boundary or extent that instrument lines are to be leak tested. The PMT does not specifically state that leak testing should be performed on instrument lines in the immediate area of the seals. As a result, operations personnel who performed the PMT on Cell 31-3-3 understood this requirement to only apply to instrument line connections that had been disconnected during maintenance. As a result, soap bubble leak testing on the cracked BOP purge line was not conducted prior to placing the cell in service. The lack of guidance regarding the equipment to be included in the leak test boundary is a contributing cause to this event.
Since it is not practical to change the design of the motor side compressor housing to provide additional work space, improvements to the PMT performed following maintenance is the most practical way to prevent a recurrence of this event. PMT will be expanded to include leak testing ofinstrument lines inside the seal area.
The UF release was similar to the types ofleaks described in the Safety Analysis Report (SAR),
Section 4.1.1.3.1, which states, "Small amounts of UF and other toxic materials such as HF, CLF3 and UO F can be released during sampling operations, seal changes, failure to obtain sufficient cell 22 and piping UF negatives, ruptured copper tubing and possibly through buffer systems. These 6
releases are prevented primarily by the use of engineering and administrative controls. To protect
~
the operator in the unlikely event a release does occur, operating specifications require that personnel performing operations and maintenance, where the possibility of release exists, wear protective j
equipment such as an individually fitted gas mask. Releases in these cases may mean that few grams of UF will escape to the' atmosphere. There are no TSR systems (Safety Systems) to prevent the 6
release of UF, while performing these types of operations. Engineering and administrative controh are considered adequate."
t
J o
GDP 99-2019 Page 3 of 4 Event Report 99-05 Corrective Actions 1.
On April 8,1999, the failed 31-3-3 stage 8 BOP purge line was replaced.
2.
By June 23, 1999, a lessons learned will be developed and issued on this event to Maintenance Mechanics that work on process gas equipment. The lessons learned will
. discuss the importance of not damaging delicate instrument lines when working in cramped quarters.
3.
13y June 23,1999, a lessons leamed will be developed and issued on this event to cascade operations personnel who perform leak testing. The lessons learned will discuss the importance of soap tests conducted on cells operating above atmospheric pressure. The lessons learned will emphasize the importance of testing instrument lines in close proximity to the applicable maintenance activity, to ensure that possible damage resulting from the maintenance activity is evaluated for leaks.
4.
By July 15,1999, procedure XP4-CO-CA2131 A, will be changed to include soap testing of instrument lines inside the seal area from their origin in the seal area to the first bracket outside the compressor.
5.
By July 15,1999, applicable seal replacement PMTs, including PMT-ME-1998-0102, will be changed to include soap testing ofinstrument lines inside the seal area from their origin at the seal to the first bracket outside the compressor.
6.
By July 23,1999, compressor seal maintenance procedures will be changed to instruct personnel working in the seal area to use caution during work activities to prevent damage to equipment such as instrument lines.
Extent of Exposure ofIndividuals to Radiation or Radioactive Materials No personnel were required to submit special urine samples based on the Plant Shift Superintendent's evaluation of the Emergency Monitoring Teams. data which indicated air and removable contamination levels were less than detectable. Follow up surveya performed by IIP confirmed minimal contamination to be present.
4 GDP 99-2019 Page 4 of 4 Event Report 99-05 Lessons Learned Event Report 98-14 discusses a similar event where maintenance _iivities resulted in damage to instrument lines located in the area of the work activity. Corrective actions for Event Report 98-14 were focused on increasing personnel awareness of the need to avoid contact with small diameter instrument lines. Continued vigilance by personnel working in tight quarters will also be
- emphasized as a result of this event. This event also demonstrates the need to improve PMT
- requirements to increase the likelihood that damaged instrument lines are detected and repaired prior to being placed in service.
I I
V L
l l
GDP 99-2019 l
Page1ofI Event Report 99-05 List of Commitments
- 1.
By June 23, 1999, a lessons learned will be developed and issued on this event to Maintenance Mechanics that work on process gas equipment. The lessons learned will discuss the importance of not damaging ( 'icate instrument lines when working in cramped quarters.
2.
By June 23,1999, a lessons leamed will be developed and issued on this event to cascade operations personnel who perform leak testing. The lessons learned will discuss the importance of soap tests conducted on cells operating above atmospheric pressure. The lessons leamed will emphasize the importance of testing instrument lines in close proximity to the applicable maintenance activity, to ensure that possible damage resulting from the maintenance activity is evaluated for leaks.
3.
By July 15,1999, procedure XP4-CO-CA2131 A, will be changed to include soap testing of instrument lines inside the seal area from their origin in the seal area to the first bracket outside the compressor.
4, By July 15,1999, applicable seal replacement PMTs, including PMT-ME-1998-0102, will be changed to include soap testing ofinstrument lines inside the seal area from their origin at the seal to the first bracket outside the compressor.
5.
By July-23,1999, compressor seal maintenance procedures will be changed to instruct personnel working in the seal area to use caution during work activities to prevent damage to equipment such as instrument lines.
'
- Regulatory commitments contained in this document are listed here. Other actions listed in this submittal are not j
considered regulatory commitments in that they are either statements or actions completed, or they are considered enhancements to USEC's investigation, procedures, or op: rations.
l
[-