ML19256E659
| ML19256E659 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/28/1972 |
| From: | John Miller Metropolitan Edison Co |
| To: | Kruesi R US Atomic Energy Commission (AEC) |
| References | |
| NUDOCS 7911130555 | |
| Download: ML19256E659 (2) | |
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j mia ia. ~wru METROPOLITAN EDlSON COMPANY u as:ciar ceae:sesst eueticuritiriesconeonarica POST OFFICE BOX 542 READING, PENNSYLVANI A 196o3 TELEPHONE 215 - 929-2601 Mr. R. Kruesi, Director Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D. C.
20545
SUBJECT:
THREE MILE ISLAND NUCLEAR STATION DOCKET NOS. 50-289 AND 50-320 REACIOR COOLANT SYSTEM CONTAMINATION
REFERENCE:
AEC/DRO LETTER DATED OCTOBER 17, 1972
Dear Mr. Kruesi:
i The referenced letter cited Metropolitan Edison Company for failing to l
report an incident which occurred on July 28, 1972, during the atte=pted s tress relievine of reactor coolant piping weld joint No. 4.
It was not considered j
by Met Ed that this incident was reportable.
i DESCRIPTION OF INCIDENT Smoke was observed coming from the area of the weld joint while the stress relieving temperature was being increased. The resistance heaters were de-energized and the area was allowed to cool. An inspection of weld joint i
4 disclosed what was later determined by chemical analysis to be a piece No.
of polyvinyl chloride resting on the insulation blanket covering the internally mounted resistance heaters. The object has melted causing a black tar-like i
substance in the im::ediate area of the joint and a smoke depost on the l
remaining reactor coolant piping and reactor vessel cladding. A chemical analy. sis resulted in chloride levels as hich as 100,000 micrograms per square
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foot in the tar-like substance, and approximately 4,000 micrograes per square
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. foot in the. smoke deposit area.
CORRECTIVE ' ACTION O
A cleaning procedure was developed and the affected area was cleaned with a solution of trisodium phosphate to recove the chlorides. Concurrent l
with the cleaning process, tests for chlorides were performed to verify the 1647 360 7911180 b p
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Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations t
l effectiveness of the cleaning procedure. The final chemical analysis showed that chloride levels had been reduced to a few hundred micrograms per square foot in accessible areas and less than 5,000 micrograms per square foot in inaccessible areas. Results are available at the Three Mile Island site for your review.
The effect of chloride contamination has been evaluated and it is considered that this occurrence should not cause any linear indications in the cladding. A liquid penetrant inspection of the cladding was performed in the circumferential area and eight inches on either side of weld joint No. 4.
No inclications were detected.
Stress relieving operations were then resumed.
The Quality Control Inspector performed a thorough inspection of the stress relieving area to ensure no foreign material existed.
PREVENTIVE MEASUPIS This incident is not expected to occur again on Unit 1 since all l
stress relieving operations were completed on September 26, 1972.
When stress relieving operations are scheduled on Unit 2, polyvinyl chloride will be prohibited inside the primary piping and reactor vessel.
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Very truly yours, 3f7 E
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G7'D~Y7 C/
J7 C. Miller Vi'ce President
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Pz. J. P. O'Reilly, Director Directorate of Regulatory Operations Region 1 i
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