ML20085F659
| ML20085F659 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 08/19/1974 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085F653 | List: |
| References | |
| AO-74-14, NUDOCS 8308230123 | |
| Download: ML20085F659 (3) | |
Text
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General Offices: 212 West Michegan Aversue, Jackson, Michigan 49201. Area Code S17 788 OSSO August 19, 1974 N
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Directorate of Licensing Re: Docket 50-255 US Atomic Energy Commission hiiids
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Washington, DC 20545 Palisades Plant m
A0-74-lh Gentlemen:
By letter dated July 22, 1974, Consumers Power Company provided a preliminary report of an abnormal occurrence (No Th-14) at the Palisades Plant on July ll, 1974. This abnormal occurrence involved the High-Pressure Safety Injection Pump P-66A.
The investigation of this occurrence has now been completed and the attached report is submitted.
Yours very truly, Ralph B. Sewell (Signed)
DAB /smm Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USAEC
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00i'Y SINF 1?EGION L
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ABN09 MAL OCCURRENCE REPORT A0-Th-lh Palisades Plant 1.
Report No - A0-74-14, Docket 50-255 2a.
Report Dates - July 22, 197h and August 19, 1974 2b.
Occurrence Date - July 11, 1974 3
Facility - Palisades Plant 4.
Identification of Occurrence - Lov discharge pressure, High-Pressure Safety Injection Pump P-66A.
5 Condition Prior to Occurrence - Cold shutdown.
6.
Description of Occurrence - During quarterly testing of the high-pressure safety injection pump, the shutoff discharge pressure was sufficiently below rated to raise the question of possible pump degradation. Shutoff head during the original manufacturer's test was 2,050 feet of water; however, during the quarterly test the shutoff head was observed to be 2,537 feet of water.
7 Designation of Apparent Cause (Design / Operation) - Disassembly of the pump showed that the sixth stage impeller had moved outboard on the shaft and rubbed on the upper and lower pump half cases causing considerable damage.
8.
Analysis of Occurrence - Normal thrust forces on the impeller are in the outboard direction. A surge could move the impe11ers inboard, allowing the spilt locking ring to fall off the shaft, which would then allow the impeller to move outboard against the casing. Such a surge could be caused by starting the pump with the suction valve clcsed and then opening it.
The possibility also exists that locking ring could have fallen off the shaft due to either a manufacturing or installation defect.
9 Corrective Action - Corrective action and action to prevent recurrence will be accomplished as follows:
The pump will be repaired and tested by the manufacturer in a.
accordance with applicable ccdes to meet original performance specifications, b.
Setscrews will be installed by the manufacturer in the shaft on the inboard side of all impellers on Pump P-66A to prevent impeller movement.
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Identical Pumps P-66B and C will be inspected and have set-screws installed in the shafts during the next refueling outage.
d.
Operating personnel will be briefed on this abnormal occurrence.
e.
A standard pump performance test procedure will be developed, f.
The high-pressure safety injection pumps will continue to be tested at least quarterly as required by the Technical Specifi-cations.
10.
Failure Date - No failure of this type has been observed; however, plant records show that a previous problem vith this pump did occur during the initial plant start-up pe'riod. This problem was found to have been caused by foreign materials (dirt and sand) passing through the pump.
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