ML20086E893
| ML20086E893 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 08/11/1972 |
| From: | GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER |
| To: | |
| Shared Package | |
| ML20086E890 | List: |
| References | |
| NUDOCS 8312080169 | |
| Download: ML20086E893 (3) | |
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2 INCIDENT REPORT 5:
k FACILITY:
Fort St. Vrain n:
1 DATE OF INCIDENT:
Late May 1972 through early July 1972 TIME OF INCIDENT:.
N/A
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INCIDENT
SUBJECT:
Corrosion on 7 Spare Control & Orificing Assemblics E
F E
1.
Description of Incident & General Designation of Apparent Cause:
r Design Material Personnel X
Procedurc X
Other
.The seven spare Control & Orificing Assemblids (CEO Assy.) were exposed
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'to an abncrmal eterage condition. An on-site campling inspection revealed the presence of corrosion to a degree which requires returning thcae units P
to the manuf acturer (Culf General Atomic, San Diego) for disassembly, a
inspection, refurbishment and test check-out.
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I 2.
Operating Conditiona of the Facility at Time of Incident:
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Hot Flow Testing Phase.
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E 3.
Immediate Evaluation - Corrective Action Taken and Results:
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'When attempting to operate one of the seven spare units during Cold Checkout F
Tests, it was found that the rod drive motor would not operate.
A similar g
condition existed when attempting to operate a second unit. Also, orifice
. valve operation was faulty on the one unit attempted.
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in The rod drive motor was disassembled in the presence of the cognizant b
engineer.
Corrosion products of a loosely adheri n, nature were present E
on the rotor and on both inside and outside surfacas of the stator.
It was.cvident that the motor " air gap" had been filled with corrosion products.
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INCIrDl:NT REPORT Page Two Visual examination of exterior portions of the assembly s!' owed the solid fila lubrication surfaces of the orifice valve, the housing surfaces, and carbon steel slips and fittings tr have been affected by corrosion.
4.
Is Foriher Eva lua t inn or Correc t Ive Ac t ion Mecessary:
Yes, after disassembly and as required, to deternine the complete extent of corrosion.
Corrective act ion necessary consis ts of (1) refurbishing, as necessary, all 3, pare units, (2) providing and implementing improved procedural controls for storage of equipment.
1 5.
Eva l u.it ion :
All f.e ve n spat, unitt were stored in a vertical position along a wall of the re.mtor ioon following receiving inspection.
The units were individually en( l o:,e u by polyethylene barrier paper.
i>o : iun t bj e r,t o r.y'e period, about 1 ate May, the F1attevil1e, Colorado, area v.e hit by nevire rainstorm accoupanied by heavy uinds of intensity suffi-( iv ut to blos open the buildi.g louvers The motive gas had not been
- , u p p l i e d to the c ont rol system to maintain the louvers in the closed po: i t ion.
After the storm, reports are that pools of water vere seen inside the po!yethylene bags.
The units were subsequently inserted into t i,e equipo"ot
.t m ane wel l s (af ter draini.ng of the rainwater).
No corrosion was evident at that time.
Ambient average tenperature of the storage wells at time of insertion was es t iiu t ed t o be 110'F. ahereas the reactor room average temperature was in the ~/ O - 80 degree range.
Stay time for the assemblics n the storage wells was about 4 wecia, It was conclnded that the cause of rusting was initially due to the wetting of the assembly which created a humid atmosphere when the assemblies were inserted into the equipment storage wells.
6.
Temporary Co r r e c t i ve Action Taken:
The equipment storage wells were evacuated to a pressure of 26 inches of water absolut e and maintained for a period of 24 to 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> to remove remaining moisture from the inserted units.
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II;CIDENT pIPORT o
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. Page Threc 7.
Per.mnent Corrective Action Taken or Recommended:
Procedural contruis and enforcement will be made more stringent to require:
a.
That the C&O assemblics are to be stored in the equipment storage wells and in a protective environment of helium.
(This is a standard operating procedure during plant operation.)
I 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).
c.
That Site QA is to provide more frequent surveillance inspections 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 assemblies in that building.
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