05000445/FIN-2008007-01
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Finding | |
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| Title | Failure to Correctly Test the Primary Plant Ventilation System (Section 2PS1) |
| Description | On February 26, 2008, the team observed in-place filter testing on the primary plant ventilation system. The primary plant ventilation exhaust filter (Unit X-15) contained two banks of high efficiency particulate air (HEPA) filters, separated by charcoal adsorbers. The testing was performed by licensee personnel and generally followed the the guidance in Regulatory Guide 1.52 and ANSI/ASME N510 1980, in which the HEPA filters are tested by injecting dioctyl phthalate (DOP) aerosol upstream of the filters with the system fan or an auxiliary blower operating. DOP concentration measurements are made upstream and downstream of the HEPA filters and percent penetration is calculated from the ratio of DOP concentrations in the filtered air (downstream reading) and the unfiltered air (upstream reading). The penetration must be less than one percent for the primary plant ventilation system. The team identified problems with the implementation of the licensees testing program which could cause a failure to collect representative DOP (particulate) samples and, therefore, non-conservative test results. The licensee did not use sampling nozzles, pitot tubes, or similar devices to ensure particulates were collected from the air stream. Instead, the licensee used flexible plastic, small-diameter tubing (0.19-inch inside diameter) inserted into larger hoses or ducts. During the test of the first bank of HEPA filters, a manifold was used for sampling the downstream air. The manifold was attached to a hose (1-inch inside diameter) which, in turn, was attached to a vacuum cleaner (flow rate unknown by the licensee). One end of a flexible tube was inserted into the hose between the point where exited the air cleaning unit and the vacuum cleaner. The other end was attached to a penetrometer equipped with a light-scattering aerosol photometer. There was no sampling nozzle and no means of ensuring the end of the tubing was pointed into the air stream. Consequently, there was no means of ensuring the air sample collected was representative of actual DOP concentration in hose. The engineer performing the test stated he had been careful to ensure the tubing was pointed into the air stream. However, the team could not verify this because the duct tape used to secure the tubing into the hose prevented observation. Additionally, the team noted the surveillance test procedure (PPT-SX-7509A, Revision 0) provided no detailed guidance for setting up the test equipment correctly and consistently. This was dependent on the knowledge of the individual conducting the testing. To measure the downstream concentration after the second bank of HEPA filters, the licensee inserted one end of a piece of a flexible plastic tube to approximately the center of a large duct (approximately 3.2 feet inside diameter) in which the air velocity was approximately 1700 feet per minute. The other end was attached to the penetrometer. Without a rigid sampling nozzle or similar device, the flexible tube likely was pointing in the direction of the air flow, rather than into it. Consequently, the penetrometer sampling pump had to capture particles traveling at the speed of the air stream and change their direction as much as 180 degrees in order to collect and count them. The failure to capture and count DOP particles downstream of the HEPA filters results in nonconservative test results and could give a false indication the filters had successfully passed the acceptance criteria. Engineering representatives stated this method had been established by vendor personnel before commercial operation and had been used by licensee personnel since that time. Further, the licensee believed it could confirm through testing the equipment configured this way provided representative test results; however it would not be able to until May 2008, after the Unit 2 refueling outage Therefore, this item will remain unresolved, pending the results of further testing by the licensee |
| Site: | Comanche Peak  |
|---|---|
| Report | IR 05000445/2008007 Section 2PS1 |
| Date counted | Mar 31, 2008 (2008Q1) |
| Type: | URI: |
| cornerstone | Barrier Integrity |
| Identified by: | Self-revealing |
| Inspection Procedure: | IP 71122.01 |
| Inspectors (proximate) | L Ricketson M Shannon G Guerra D Stearns L Carson D Gravesl Ricketsonj Dixon K Clayton B Tharakan L Carson G Replogle B Tindell M Bloodgood D Reinert G Tutak J Kramer N Okonkwo N Hernandezj Braistedp Goldberg G Guerra C Smith G Pick W Walker B Tindell W Sifre M Young A Fairbanks J Kramer |
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Finding - Comanche Peak - IR 05000445/2008007 | |||||||||||||||||||||||||||
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Finding List (Comanche Peak) @ 2008Q1
Self-Identified List (Comanche Peak)
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