ML20211N895

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Forwards Required 30 Day Event Rept 99-17,for Event That Resulted from Determination That 13 Sprinkler Sys Associated with High Pressure Fire Water Sys in Process Buildings Were Not Capable of Meeting Operability Requirements
ML20211N895
Person / Time
Site: Portsmouth Gaseous Diffusion Plant
Issue date: 09/07/1999
From: Jonathan Brown
UNITED STATES ENRICHMENT CORP. (USEC)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GDP-99-2052, NUDOCS 9909130101
Download: ML20211N895 (5)


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d.USEC A GW Energy Company l

September 7,1999 GDP 99-2052.

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 99-17 Pursuant to 10CFR76.120(d)(2), Enclosure 1 provides the required 30 day Event Report for an event that resulted from the detennination that 13 sprinkler systems associated with the High Pressure Fire Water system in the process buildings were not capable of meeting operability requirements at the Portsmouth Gaseous Diffusion Plant. Investigation and testing activities are continuing to determine the root cause and corrective actions for this event. The revised report is scheduled for October 3, 1999. There are no commitments contained in this report.

Should you require additional information regarding this event, please contact Scott Scholl at (740) 897-2373.

Sincerely, h

. Morris Brown General Manager Portsmouth Gaseous Diffusion Plant j

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Enclosures:

As Stated M

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NRC Region 111 Office jQ NRC Resident inspector - PORTS g

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9909130101 990907 PDR ADOCK 07007002 PDR

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United States Enrichment Corporation Portsmouth Gaseous Diffusion Plant P.O. Box 628, Piketon, OH 45661 i

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GDP 99-2052 Page1of4 Event Report 99-17 Description of Event

~ On August 10,1999, at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />, the Plant Shift Superintendent was notified that 13 sprinkler systems associated with the High Pressure Fire Water (HPFW) system were not capable of meeting

- system' operability requirements. This condition was discovered as a result of an engineering walkdown ofindividual sprinkler heads that had previously been identified as exhibiting corrosion around the valve seat.' The sprinkler heads were not externally corroded, but rather leaking at the seat. The visible deposit is a build-up of dissolved solids left by evaporating water that leaked past the seat. The engineering review was conducted following the discovery that similar problems experienced at the Paducah Gaseous Diffusion Plant (PGDP) resulted in sprinkler heads being unable to actuate at the required pressure. The failure of the HPFW system was reportable in accordance

'with 10CFR76.120(c)(2). A brief history of events leading to the discovery of this condition is presented below.-

On April 16,1997, the Portsmouth Gaseous Diffusion Plant (PORTS) initiated a walkdown of the fire sprinkler system in response to IIPFW piping deficiencies discovered at PGDP. The purpose of the walkdown was to identify any disconnected sprinkler piping branch lines and to find other system deficiencies.

On June 27,1997, five heads were discovered under ductwork in the X-333 Process Building that had a buildup of mineral deposits. Since the impact of mineral deposits on the ability of the sprinkler heads to function was not known, the individual heads were declared inoperable and were replaced. Six additional heads with mineral deposits were discovered on October 16,1997, and were also assumed to be inoperable. An operability evaluation determined that, because of overlapping coverage of the sprinkler heads and the location of adjacent sprinkler heads, the sprinkler system remained operable, even ifindividual heads would not operate. The walkdown continued through November 1997, and additional heads with mineral deposits were discovered.

.To determine the impact of mineral deposits on sprinkler head operability,12 sprinkler heads exhibiting m'neral deposits were sent to the PORTS laboratory for testing and evaluation. The testing determined that the heads would operate at the proper temperature, but operated at pressures greater than the expected 5 to 7 psi. The available pressures on the sprinkler systems at PORTS will vary from 7 to 125 psi depending on the location of the head, the elevation and number of heads operating and associated friction losses. The typical pressure available to operate a single head under ductwork in a process building is approximately 105 psi. Since this information provided reasonable assurance that mineral deposits did not prevent the heads from operating, sprinkler heads having mineral deposits were no longer assumed to be inoperable.

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GDP 99-2052 Page 2 of 4 Event Report 99-17 Four additional heads with mineral deposits were sent to the manufacturer (Grinnell Corporation) for evaluation and were determined to be within the acceptable range of operation. Both the PORTS laboratory and the manufacturer identified that the copper gasket was deteriorated.

On June 2,1999, the annual PGDP Fire Services walkdown of the sprinkler systems found deposits

'on 81 heads affecting 17 systems (event report PAD-1999-040). Subsequent inspections found

' cotrosion on 18 additional heads. The sprinklers were declared inoperable and TSR actions were taken and replacement initiated. Operational and metallurgical testing of sprinkler heads by Factory Mutual (FM) was requested by PGDP and PORTS. (FM is USEC's insurance carrier and is a

. nationally recognized testing agency).' The test results indicate that the heads work, but some require elevated pressures to activate. Two of twelve PGDP heads activated at 120 psi.

Based upon the PGDP discovery that mineral deposits could prevent sprinkler heads from operating

. at HPFW pressures, PORTS conservativly declared individual corroded sprinkler heads inoperable pending further evaluation and testing. A walkdown of 27 systems containing sprinkler heads with

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previously identified mineral deposits was performed.' The walkdown resulted in 13 systems being declared inoperable because adjacent heads were inoperable. TSR required actions were initiated and 66 heads were changed to restore system operability. As noted earlier, the sprinkler heads that were previously identified as having mineral deposits were believed to be operable because testing indicated that mineral deposits did not prevent sprinkler head operation at HPFW pressures.

- Additional walkdowns of process building sprinkler systems were initiated to identify additional sprinkler heads that may have external mineral deposits. On August 19,1999, at 1038 hours0.012 days <br />0.288 hours <br />0.00172 weeks <br />3.94959e-4 months <br />, one additional system'was declared inoperable when three adjacent heads having deposits were j

. discovered. The system was repaired at 1407 hours0.0163 days <br />0.391 hours <br />0.00233 weeks <br />5.353635e-4 months <br />.

i On August 27,1999, at 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br />, five additional sprinkler systems were declared inoperable with two or more adjacent heads unable to meet system operability. All sprinklers were repaired and the j

systems were declared operable at 0550 hours0.00637 days <br />0.153 hours <br />9.093915e-4 weeks <br />2.09275e-4 months <br /> on August 28,1999.

On August 30,1999, seven additional sprinkler systems were declared inoperable with two or more adjacent. heads unable to meet system operability. Six systems were in X-333 and one system was in X-330. All sprinklers were repaired and the systems were declared operable at 1258 hours0.0146 days <br />0.349 hours <br />0.00208 weeks <br />4.78669e-4 months <br /> on August 31,1999.

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. On August 31,1999, seven additional sprinkler systems were declared inoperable with two or more

' adjacent heads unable to meet system operability. System repairs are continuing.

L GDP 99-2052 Page 3 of 4 Event Report 99-17 On September 1,1999, fourteen additional sprinkler systems were declared inoperable with two or more adjacent heads unable to meet system operability. System repairs are continuing. Walkdowns to discover other inoperable heads or systems are continuing.

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There are approximately 98,000 sprinkler heads in the process buildings at PORTS. The total number of sprinkler heads with extemal mineral deposits discovered between 1997, and August 19, 1999, was approximately 119. The breakdown by building was: 90 in X-333; 22 in X-330; 7 in X-326.

The majority of the sprinkler heads in the process buildings were manufactured by Orinnell Corporation and installed in the late 1950's and early 1960's. Sprinkler h ads have a life expectancy of at least 50 years with a code required inspection program after 50 yevs.

Cause of Event The direct cause of the sprinkler heads operating at higher than expected pressure was mineral l

deposits on the' sprinkler heads due to 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, sodium.

i The analysis to determine the root cause ofleakage has not been completed. Preliminary results indicate 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". The analysis to determine the cause of the seal deterioration and the effect of the resulting deposits on the heads'

_ operability has not been completed. PGDP is involved in the investigation and the issue has been j-discussed with representatives of FM and Grinnell Corporation.

In addition to the PORTS and PGDP ongoing testing activities to determine the root cause, PORTS has requested FM to test sprinkler heads that have resulted b IIPFW systems being declared I

inoperable. The purpose of the testing is to determine the pressure required to operate the heads.

The results of this testing will be used to determine if the individual corroded heads were actually i

inoperable as a result of the mineral buildup. The conservative decision to declare systems inoperable based on the existence of two adjacent corroded heads will then be reassessed to determine the actual impact on liPFW system operability.

Representatives from BETZ Dearborn Water Management Group have been requested by PGDP to assist in determining whether the cause of the deterioration of the copper gasket is due to water chemistry. Water sample analysis will aid in determining the cause and scope of the water chemistry

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problem. Further water testing may be done at PORTS if other analyses are not conclusive.

l GDP 99-2052 Page 4 of 4 1

Event Report 99-17 The results of the sprinkler head testing and water chemistry testing will be used to determine the root cause and con ective actions necessary to correct the problem. This report will be revised when these actions are complete.

The investigation has also noted that plant personnel did not recognize the potential safety significance of the degraded sprinkler heads when they were discovered and did not promptly initiate repairs. The replacement of the sprinkler heads identified in 1997, as having deposits was given a lower work order priority (priority 6) than those established for routine maintenance (priority 7). The belief that mineral deposits did not make the sprinkler heads inoperable led to the perception that sprinkler head replacement could be performed as lower priority work. As a result, the sprinkler heads identified between 1997, and August 1999, were not replaced until after the HPFW systems 1

were declared inoperable.

Corrective Actions Corrective actions will be provided with the revised event report.

Extent of Exposure ofIndividuals to Radiation or Radioactive Materials There was no exposure to radiation or radioactive materials due to this event.

Lessons Learned Lessons Leamed will be provided with the revised event report.

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