ML20086E215
| ML20086E215 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 04/09/1974 |
| From: | Swart F, Warembourg D PUBLIC SERVICE CO. OF COLORADO |
| To: | |
| Shared Package | |
| ML20086E212 | List: |
| References | |
| AO-50-267-74-2A, NUDOCS 8312060277 | |
| Download: ML20086E215 (4) | |
Text
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DATE: April 9, 1974 ABNORMAL OCCURRENCE X
FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 Platteville, Colorado -80651 REPORT No.
50-267/74/2A Interim Final X
IDENTIFICATION OF OCCURRENCE:
This report is issued to finalize the Interim Report 50-267/74/2 dated Jan. 14, 1974, concerning graphite reflector block discrepancies found during initial fuel loading.
This event is considered to be an abnormal occurrence as defined in The Technical Specifications, paragraph 2.1F.
CONDITIONS PRIOR TO OCCURRENCE:
Steady State Power Routine Shutdown Hot Shutdown Routine Load Change Cold Shutdown X
Other (specify)'
Refueling Shutdown Initial Fuel Loading Routine Startup The Major plant parameters at the time of the event were as follows:
5 POWER
.RTR, N/A MWth J
- Elect, N/A NWe-Secondary Coolant Pressure _
N/A psig Temperature N/A
' F Flow N/A-
- /hr.
Primary Coolant Pressure N/A psig
-Temperature N/A F Core Inlet F312060277 740114
'N/A' F Core Outlet.
PDR ADOCK 05000267 S
PDR Flow N/A
~#/hr.
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50-267/74/2A Page 2 4
DESCRIPTION OF OCCURRENCES:
On Saturday, January 12, 1974, inspection of the permanent half size l
top reflector to be installed in layer two of the Fort St. Vrain reactor, revealed 12 elements that did not meet the specifications for chips-and gouges. One element was found to have an off-center drilled dowel hole.
Spare reflectors were substituted for five of these out-of-specification blocks. To facilitate continued testing, these seven out-of-specification t
reflectors were installed in the reactor in layer 2 and layer 3, Column 7 of region 6.
These seven (7) out-of-specification blocks were subsequently replaced with new blocks. All blocks were accounted for by~ serial number.
APPARENT CAUSE OF OCCURRENCE:
Design Unusual Service Cond.
Including Environment j
X Manufacture Component Failure Installation /Const.
Other (specify)
Operator X
Procedure ANALYSIS OF OCCURRENCE:
I These discrepancies were investigated by General Atomic to determine the i
cause of the damage and to determine changes required'in QA/QC procedures.
l The cause of rejection of the major portion of the graphite reflector block was chips found on the bottoms of the elements at the edges of coolant holes.
A review of the damage related to time af manufacture, inspection or shipment.
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. indicates that the damage experienced was strictly random in' nature.' Damage could not be traced to any particular process or time when. inspection might-have been lax.
It is felt that the damage observed resulted from setting the elements down on a relatively hard surface with some foreign material between-the element and the surface.
Procedural modifications have been initiated'to include the use of a non-rigid support that could accommodate a:small amount of' debris under'
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' l the element..This support,would prevent damage during the normal handling
. process. In addition, procedural changes have been initiated to provide l
for a 100% inspection of the element, with special emphasis on the bottom surface, prior to packaging for shipment.
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Other procedural changes that have been initiated include an inspection-l of all coolant holes and grapple holes for foreign material that could drop out.
Pictorial element diagrams will.be used in'the inspection of each block to record any damage observed.
In conjunction with this pictorial i
record, the fuel / reflector assembly record procedures are to be modified to require that all significant damage be documented.
GA has also initiated inquiries to Great Lakes Carbon concerning the1r inspection and handling efforts, and GA has also initiated some training-j sessions at Great Lakes Carbon to inform.them of the requirements of the fuel program and 10CFR50, App. B.
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CORRECTIVE ACTION:
l Replacement reflector blocks were received from Great Lakes Carbon.
Site receiving inspection revealed no discrepancies.:.Seven (7) rejected i
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elements were removed from the core, properly documented by serial number, and replaced with new elements.
Procedural changes initiated by GA to improve handling and. inspection-I appears to be adequate. An audit conducted by PSC.on 4/2/74 indicates that-i GA has.taken action to initiate changes. PSC will; provide follow-up; audits f~
. prior to shipment of'the first reload'to ' confirm that changes.have been t
I implemented.
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FAILURE DATA /SIMILAR REPORTED OCCURRENCES:
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No failure of this type L ad previously been experienced.
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Page 4 PROGRAMMATIC IMPACT:
No programmatic ~ impact will be experienced insofar as out-of-specification.
Reflectors were used to continue loading and to facilitate initial phases of low power physics testing in air.
CODE IMPACT:
No Code involved.
t Prepared By:
Approved:
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Don Warembourg
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Bfederic E.. Swart Director, Quality Assurance Superintendent, Fort St. Vrain Nuclear Generating Station 1
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