ML20084T380
| ML20084T380 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 07/28/1970 |
| From: | Swarts K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084T381 | List: |
| References | |
| NUDOCS 8306230163 | |
| Download: ML20084T380 (3) | |
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517 788-0550 July 28, 1970 Re: Docket No 50-255 Dr. Peter A. Marris, Director Division of Reactor Licensing US Atomic Energy Commiosion Washington, DC 20545
Dear Dr. Morris:
The following summary description of a demineralizer and resin release problem'at the Palisades Plant is forwarded for your use. This problem has previously been discussed with Region III Compliance and this sunmary which covers the event and its resolu-tion is intended for infomational purposes.
General During a hot functional test run in the period of April 23 through April 25, 1970, laboratory personnel noted indications of resins in a primary system water sample taken from the No 2 hot loop sample point (SX-lo23) at 0700 on April 25. About 29 hours3.356481e-4 days <br />0.00806 hours <br />4.794974e-5 weeks <br />1.10345e-5 months <br /> earlier an increase in the primary loop hydrogen concentration had been noted by a recording gas analyzer on the volume control tank. At the time the resins were noted, the plant was being cooled down due to diffi-culties encountered with pump seals.
An investigation of the source of these resins was made by disassembly of the two purification and one deborating demineralizers.
The release was determined to be mainly due to the slow release of resin from the deborating demineralizer. The resin migrated under the periphery of the retention screens at a few places where the retaining rings and/or spacer rings were not properly fabricated and installed (bolts not tightened). Two purification filters (F54A, F54B) down-stream of the demineralizers were opened and inspected. F54B was found to be in good condition with a few resin fines noted in the filter.
F54A was found to have several crushed filter columns and sczne filter columna detached from the end plate.
It was detemined that Filter F54A had accumulated resin from the defective demineralizers during the first hot functional test run and subsequently failed during the second run due to a high differential pressure across the filter. A pressure 4;e
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COPY SENT REGION 8306230163 700728 PDR ADOCK 05000255 237 /
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e Dr. Peter A. Morris 2
July 28, 1ry70 differential of at least 70 pai would be required to cause the observed damage and it is believed that a high letdown flow coupled with the resin loading led to this condition.
It is estimated that approximately 10 cubic feet of resin were released from the demineralizers.
Clean-Up A clean-up procedure was instituted and carried out which basically involved flushing all systems to the reactor vessel and then hand cleaning of the vessel after removal of core internals. Those lines or systems flushed included the chemical and volume control charging and letdown streams, safety injection and shutdom cooling lines, cnd the primary system including the steam generators, pressurizer, pri-mary coolant pumps, and the vessel.
(The control rod drive mechanisms were not installed during this testing. )
Several valves, the charging pumps, and heat exchangers were inspected for evidence of resin after the flushing operation. Smear samples were taken in the reactor vessel and other components which did not indicate chemistry conditions outside acceptable limits. These in-spections and flushing of instrument lines and sample connections in-dicate that the resin has been thoroughly cleaned from the primary system.
Repair The resin retention parts of the demineralizers were reworked as required and the reassembly thoroughly inspected. The system design was predicated on the basis that, although of low probability, a slow release of resin was considered possible, and it was thought that routine monitoring of the installed differential pressure indicator across the filters would alert the operators to a problem before excess pressure differential developed. A differential pressure alam has been installed on the existing filters to alert the operators in the control room of high filter differential pressure and thus avoid reliance on routine readings.
To provide assurance that such a resin problem will not recur, two new wye strainers are being installed, one downstream of the purifi-cation and deborating demineralizers, and the other downstream of the purification filters.
It is noted that either of these will protect from a resin release, but the addition of the second strainer downstream of the filters also provides protection against the release of any mate-I rial from the filters. These strainers are designed for a differential pressure of 300 pai which provides a 100 psi margin above the maximum i
l source pressure of 200 psig (RV-2013 setting).
Chemistry I
l The maximum chloride concentration noted during this period was 0.69 ppm which decreased after start of cooldown probably due to dilution.
Combustion Engineering (CE) has since conducted several laboratory auto-clave tests with stressed samples representative of Palisades system sur-faces. These tests used resin concentrations approximately 10 times L
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Dr. PC,ttr A. Morris 3
July 28, 1970 those estimated in the Palisades system and resulted in chloride concen-trations of 8.5 times those noted in the Palisades system. Analysis of the autoclave steam phase showed the presence of resin degradation pro-ducts in the form of halogenated hydrocarbons, low molecular weight amines frcxn the anion resin, and sulfur dioxide from the degradation of the cation resin. None of these substances are considered corrosive to the metal surfaces of the primary system at the concentrations observed.
Visual and microscopic examination of the specimens after the tests (136 hours0.00157 days <br />0.0378 hours <br />2.248677e-4 weeks <br />5.1748e-5 months <br /> autoclave at 53o F and 23 days at Palisades water conditions) showed no evidence of attack by the resin degradation products even at the increased concentrations over the Palisades conditions.
It is con-cluded that the corrosive effects of the introduced resin on the Palisades primary system surfaces are negligible.
Conclusions Approximately 22 days of clean-up activities were required to ensure the return of the primary system to a clean condition. This prob-lem points up the need for thorough shop and subsequent field inspection of such components before placement into service. No pemanent damage was inflicted to the system by this resin release. The only potential deleterious effect noted was the increase in chloride concentration to a maximum of 0.69 ppm associated with the resin decomposition. This magni-tude of chloride transient is not considered detrimental.
Yours very truly,
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KAS/ch K. A. Swarts Project Engineer l
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