ML20211G997
| ML20211G997 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 08/26/1999 |
| From: | Pulley H UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-99-1029, NUDOCS 9909010099 | |
| Download: ML20211G997 (4) | |
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l USEC A Global Energy Company i
August 26,1999 GDP 99-1029
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United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Docket No. 70-7001 Event Report ER-99-10, Rev. 2 l
Pursuant to 10CFR76.120(d)(2), enclosed is the revised written event report pertaining to corroded fire sprinkler heads affecting the operability of high pressure fire water (HPFW) sprinkler systems in Building C-337, and Building C-333. The Nuclear Regulatory Commission (NRC) was notified of the initial event on June 3,1999 (NRC No. 35790) and updated as other notifications became necessary. At this time, the testing and analysis to determine the root cause and corrective actions necessary have not been completed. Vertical bars in the right hand margin indicate changes to the initial report dated July 30,1999.
Any questions regarding this matter should be directed to Larry Jackson at (502) 441-6796.
Sincerely,
/A General M) nager varc; Pu a
Paducah Gaseous Diffusion Plant
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Enclosures:
As Stated j
cc: NRC Region III Office NRC Resident Inspector-PGDP 9909010099 N M PDR ADOCK 07007001
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C PDR 010n28 P.O. Box 1410, Paducah. KY 42001 Telephone 502-441-5803 Fax 502-441-5801 http://www.usec.com OfTices in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC
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2 Docket No. 70-7001 GDP 99-1029 Page 1 of 3 EVENT REPORT ER-99-10, Rev. 2 l
DESCRIPTION OF EVENT-On June 2,'1999, at approximately 1630 hrs.', Fires Services personnel notified the Plant Shift Superintendent (PSS) that during the annual Fire Services building high pressure fire water
. (HPFW) sprinkler _ system re-appraisal, 66 sprinkler heads in the C-337 process building affecting 16 systems and 20 sprinkler heads in the C-333 process building affecting 1 system were noted to have a build up of corrosion products around the body of the heads. The PSS consulted with the i
plants fire protection engineer who could not provide reasonable assurance that the affected sprinkler heads could perform their design function. The PSS then declared the systems in C-337 and C-333 inoperable, and established roving fire patrols in the affected areas, as required by j
Technical Safety Requirements (TSR) General Limiting Conditions For Operations (LCO) 2.4.4.5.
On June.3,1999, at 1330 hrs., the Nuclear Regulatory Commission Headquarters (NRC-HQ) operations office was notified of the event, as required by 10CFR76.120(c)(2) and l
NRC event 35790 was assigned. Inspections of the remaining Cascade process building sprinkler systems were initiated to determine if other systems exhibited similar problems. This resulted in the discovery of two sprinkler heads in the C-335 process building, which had similar corrosion deposits affecting the operability of one system. This system was declared inoperable and LCO actions to establish a roving fire watch were implemented. At 0922 hrs., on June 4,
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'1999, NRC-HQ operations office was notified, as required by 10CFR76.120 (c)(2) and NRC No.
35790 was updated to provide this additional information.
l Subsequent to these notifications, investigation team members on June 16, 1999, identified i
corrosion on eight' sprinkler heads in C-333. The effected systems were declared inoperable and l l
- fire watches were implemented. NRC-HQ was notified and the event report (NRC No. 35790) l was updated on June 17, 1999.
' On June 18,1999, this report was again updated and NRC-HQ notified to report the discovery of three sprinkler heads in the C-333.
On June 25, 1999, the report was updated and NRC-HQ notified to report five additional l.
- sprinkler heads in C-337 with similar corrosion.
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Docket No. 70-7001
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GDP 99-1029 Page 2 of 3
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On July 30,' 1999, this report was updated and NRC-HQ notified when five additional corroded sprinkler heads were discovered in C-337. On July 31,1999, two additional corroded sprinkler heads were discovered in C-337. NRC-HQ was notified and the report was again updated. On
~ August 10, 1999, two corroded sprinkler heads were discovered in C-337 and NRC was notified and the report updated. On August 22,1999, four corroded sprinkler heads were discovered in C-333. NRC-HQ was notified and.this report updated. The total number of corroded heads l
below exceeds the numbers stated above, because operability of the system may not depend on a single head. A specific operability determination is cond' ucted when a corroded head is found and includes the number of corroded heads and location.
' For all of the above discoveries, the systems were declared inoperable, LCO actions initiated and
. actions were immediately initiated to replace the sprinkler heads affecting system operability and l
following completion of this work, the systems were declared operable and LCO actions were exited.
. The HPFW sprinkler systems in the process buildings are wet-pipe systems installed in the 1954 timeframe. The total number of sprinkler heads with external mineral deposits discovered to date l
in 1999 is 133. The breakdown by building is: (number of corroded heads / total heads) C-310
=.0/606; C-315 = 0/92; C-331 = 0/12,610; C-333 = 43/24,877; C-337 = 93/24,796; C-335 1
= 2/13,368.
The replacement of sprinkler heads with corrosion deposits, which may affect the HPFW systems operability, provides reasonable assurance that the system can perform its intended function.
CAUSE OF EVENT l
Although the analysis to determine the root cause of the event has not been completed, l
preliminary results indicate that the deposits discovered on the sprinkler heads are the results of l
water leakage and subsequent evaporation. The deposits appear to be salts associated with typical constituents of the sprinkler system water chemistry, e.g., calcium, chloride, and sodium. It appears that the leakage is caused by corrosion of the interior copper gasket, which is designed to provide a seal between the body of the sprinkler head and the sprinkler " cap" or " button" (see attached diagram). The analysis to determine the cause of the button deterioration and the effect of the resulting deposits on the heads operability has not been completed. The USEC plant at Portsmouth, Ohio is involved in the investigation and the issue has been discussed with a representative of the Factory Mutual (FM) Insurance Company and Grinnell Corporation.
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Docket No. 70-7001 GDP 99-1029 Page 3 of 3 k
In addition to the testing ongoing at Paducah and Portsmouth, FM has agreed to conduct testing l
at their laboratories to provide their expertise in this area. Several sprinkler heads have been terre /ed from the HPFWS and sent to the FM metalargy and hydraulics laboratories for testing.
A statistically based sprinkler head-sampling plan has been completed and approved. This will provide a method by which sprinkler heads will be randomly chosen and removed from the i
system for analysis and testing. This will include the removal of heads exhibiting the external l
mineral deposits and heads that do not. A laboratory procedure has been created to provide the controls for the testing of the heads that are removed. The results of this testing will be used to determine the overall effect of this problem on the HPFWS.
In addition, representatives from the Betz Dearborn Water Management Group have visited the plant and have been requested to provide their expertise to assist in determining the cause of the deterioration of the sprinkler heads copper gasket. They have agreed to assist in the development of a firewater-sampling plan and have made some recommendations. This water sampling and analysis will aid in determining the cause and scope of the water chemistry problem. Water q
samples have been drawn from various selected fire sprinkler systems, the cooling tower basins j
and HPFW tank and sent to Betz for analysis. The results of this and the sprinkler head testing effort will be used to determine the cause, the effect, and the corrective actions necessary to correct the problem. This report will be revised as the results of the testing and analysis becomes available. A target date for the next revision is September 30,1999.
EXTENT OF EXPOSURE OF INDIVIDUALS TO ' RADIATION OR TO RADIOACTIVE hiATERIALS This event does not involve radioactive materials and no exposures have occurred.
LESSONS LEARNED To Be Determined