ML20086E914
| ML20086E914 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 08/11/1972 |
| From: | Walker R PUBLIC SERVICE CO. OF COLORADO |
| To: | Kruesi F US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086E890 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8312080183 | |
| Download: ML20086E914 (4) | |
Text
F O
O j l PUBLIC SERVICE COMPANY OF COLORADO DENVER, COLORADO 80200 P. O. B O X 440 R. F. WALMER vect passdOENT August 11, 1972 Mr. F. E. Kruesi Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D. C.
20545
Subject:
Deficiency Report 10 CFR 50, Part 50.55 Control Orificing Assenblies
Dear Mr. Kmesi:
Pursuant to the reporting requirements of 10 CFR 50, Part 50.55, we are subnitting herewith as an interim report, twenty copies of an incident report involving the spare control and orificing assemblies at the Fort St.
Vrain Station. The report is considered complete but is filed as an interim report, due to the fact that the assenblies have not as yet gone through final disassenbly, and the results of the disassenbly and final inspection may re-quire further evaluation.
The Control and Orificing Assenblies are presently at-the Gulf Gen-'
eml Atanic facilities in San Diego.. Public Service Company will be' monitor-ing through our Nuclear Pbwer Consultant, the disassembly and refurbishnent of the assenblies. The results of our inspection efforts _will be made avail.
able to the local Directorate of Regulatery Operations as soon as possible after the work is completed.
We trust the attached report will provide you with sufficient infor-mation and will fulfill the reporting requirements of 10 CFR 50.
Very truly yours, R. F. Walker, Vice President.
Digineering and Planning--
Electric Department
-REW/jk1 cc: Mr. John Flora Director, Region IV - Denver
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INCIDENT REPORT
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FACILITY:
Fort St. Vrain i
DATE OF INCIDENT:
Late May 1972 through early July 1972 i
TD'E OF INCIDENT:.
N/A INCIDENT
SUBJECT:
Corrosion on 7 Spare ' Control & Orificing Assemblics
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1.
. Description of Incident & General Designation of Apparent Cause:
Design Material Personnel X
Procedurc X
Other
'.The seven spare Control & Orificing Assemblics (C&O Assy.) were exposed
'to an abnormal eterage condition.
An on-cite compling incpection revealed the p'esence of corrosion to'a degree which requires returning these units r
to the ma'nufacturer (Culf General Atomic, San Diego) for disasacably,
- inspection, refurbishment and - test check-out.
2.
Operating Conditions of the Facility at Time of Incident:
Hot Flow Testing Phase.
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_Immediate Evaluation - Corrective Action Taken and Results:
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. "When attempting to operate one of the seven spare units during Cold Check'out Tests, it was found that the rod drive motor would not operate. ' A similar condition existed when attempting to operate a second unit.
Also, orifice' valve operation was faulty on the one unit attempted.
l The rod drive motor was disassembled in the presence of the' cognizant enginecr.
Corrosion products of.a loosely adhering nature were present onsthe rotor and on both inside and outside surfaces of the' stator.
It-was. evident that 'the motor " air gap"- had been' filled with corrosion products.
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- - ', INCIDENT REPORT Tage TMo Visual examination of exterior portions of the assembly showed the solid film lubrication surfaces of the orifice valvo, the housing surfaces, and carbon steci slips and fittings ta have boon affected by corrosion.
4.
Is Further Evaluation or Corrective Action Necessary:
Yes, after disassembly and as required, to determine the complete extent of corrosion.
. Corrective action necessary consists of (1) refurbishing, as necessary, all spare units, (2) providing and implementing improved procedural controls for storage of equipment.
5.
'Evalaation:
All seven spare units were stored in a vertical position along a wall of the reactor room following receiving inspection.
The units were individually enclosed by polyethylene barrier paper.
During this storage period, about late May, the Platteville, Colorado, arca.
was hit by severe rainstorms ac' companied by heavy winds of intensity suffi-
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The motive gas had not been cient to blow open the building louvers.
supplied to the contro1' system to maintain the louvers in the closed position.
Af ter the storm, reports are that pools of water were seen Insido.the polyethylene bags. The units were subsequently insarted into
'the equipment storage' wells (af ter draining of the rainwater).
No corrosion was.cvident at that time..
Ambient average temperature of the storage volls at time of insertion was.
' estimated to be 110*F. whereas the.rcactor room' average temperature was in the 70 - 80 degree range.
Stay time for the assemblics in the storage wells
.- was about 4 wecks.
It was ' concluded that~ the cause of rusting was initially due to the wetting -
of the dssembly which created a humid -tmosphere when the assemblies were inserted into the equipment' storage wells..
6'.
Temporary Corrective Action' Taken:
The' equipment storage wells were evacuated-to a pressure of 26 inches of
. water' absolute ~and maintained for a period of 24 to 30. hours-to remove remaining noisturcLfrom.the inserted units.
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Permanent Corrective Action Taken or Recommended:
Procedural controls and enforcement will be.made more stringent.to require:
a.
That the C60 assemblics are to be stored in the equipment storage wells and in a protective environment of helium.
(This is a standard operating proceduro during plant operation.)
b.
That for periods of temporary storage such as during construction, prestart-up testing, and fuel loading, the packaging and storage requirements are to be improved to provide dry, scaled, individual containments. This is for.those units in excess of the number of equipment storage wells -(10).
That Site QA is to provide more frequent surveillance inspections c.
and feedback type reporting.
.. d.
That the control system for operating the reactor building louvers are to be in tact when handling or storing (item b.) C&O assemblics in that building.
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