ML19317G683
| ML19317G683 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/04/1972 |
| From: | Spencer G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Henderson J US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19317G673 | List: |
| References | |
| NUDOCS 8003250749 | |
| Download: ML19317G683 (3) | |
See also: IR 05000312/1972001
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UNITED STATES
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ATOMIC ENERGY COMMISSION
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OlVISION OF COMPLIANCE
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REGION V
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2111 BANCROFT WAY
BERKELEY, CALIFORNIA 94704
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May 4, 1972
J. B. Henderson, Chief
Reactor Construction Branch
Directorate of Regulatory Operations
SACRAMENTO MUNICIPAL UTILITY DISTRICT (RANCHO SECO)
DOCKET NO. 050-0312
The attached report of our recent visits to the subject construction site
on March 9, 20-24, and April 6,1972 is forwarded for headquarters action.
The March 9 and April 6 visirs were announced as they involved observation
of the placement of the reactor vessel, and a special visit at the request
of the General Accounting Office auditor currently reviewing Region V
inspection activities. Two items of nonconformance were identified during
the inspection.
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In addition to these visits, our inspector attended a meeting between SMUD
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and the State of California Division of Industrial Safety concerning the pipe
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joint welding problem, on March 31.
It appears to us that the fissures (not
carpreted to be lack of fusion)
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detected in the stainless steel pipe we F:: 4t Rancho Seco may exist throughout
construction in che nuclear field and taerefore warrants further attention
by CO and DRL. We have a rather complete file of SMUD-Bechtel memoranda
that show the evaluation of activities associated with identifying and
resolving the apparent unacceptable conditions.
SMUD informed us on April 26, 1972 that lack of fusion indications similar
to those identified in the stainless steel welds have been reproduced in
the laboratory using carbon steel pipe with a slight mismatch condition.
This information will also be included in their planned report to CO.
As
a' result of this recent information the licensee has ordered a re-examination
of all radiograph film of Class I piping welds to determine which welds
show lines indicating the potential for this type of condition. In addition
the containment penetration radiographs will be examined for this condition.
SMUD also informed us that examination of films taken of welds performed
by their pipe fabricators (Pipe Fab and Associated Pipe) revealed lines
that indicated the potential lack of fusion condition.
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J. B. Henderson
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May 4, 1972
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We also recommend that DRL be asked to evaluate the as-built condition of the
containment liner even though we expect the licensee will perform a thorough
analysis before accepting the liner in its present condition.
The licensee has agreed to transmit reports, as appropriate, concerning the
root pass fissures in the stainless steel pipe welds and the nonconformance
conditions of the containment building liner.
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A sample interpretation of containment vessel' radiographic film indicated,
in the opinion of the (CO:III) inspector, that the film was generally
unacceptable in terms of weld defect (or film defect) indications which
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were in excess of specified codes. Moreover, the corrective activities
initiated by the applicant's representatives, as documented on Rancho Seco
Nonconformance Report No. 365, do not appear to have provided adequate
assurance of acceptable weld quality for a significant portion of the contain-
ment liner welds. As you know, these welds are now practically impossible to
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repair or reradiograph. The licensee's position is that they have re-examined
the radiographs and feel the liner meets UW-51.
They also indicated that
the vacuum box soap bubble and leak rate tests will be the official bases on
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which-the liner integrity will be accepted.
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Although several questions were raised by the (CO:III) inspector regarding
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specific radiographs of Class I piping and other Class I structures, the
nondestructive testing programs, records, and radiographs, collectively,
were found to be in substantial conformance to the required codes and
procedures.
We confirmed that satisfactory corrective action has been taken on all of the
items discussed in our letter to the licensee dated January 14, 1972 and in
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ac ordance with their response dated February 7,1972.
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G. S. Spencer
Senior Reactor Inspector
Enclosure:
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CO Insp. Rpt. No. 050-0312/72-01
(Orig. + 17-copies)
cc:
R. H. Engelken, CO, w/ encl.
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L. Kornblith, CO, w/ enc 1.
CO Files, w/ enc 1.
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DIVISION OF COMPLIANCE
MONTHLY REPORT FOR APRIL 1972
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Sacramento Municinal Utility District (SMUD)(Rancho Seco) -
An inapection was conducted on March 9, 20-24, and April 6.
-Arcan examined included the QA program for installation of
f.he reactor vencel, welding of piping fabrication of Clacs I
tanka and of the containment vessel liner.
Apparent noncon-
formance with requiremento involving segregation of construc-
tion materialn and radiography acceptance standards was
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identified.
The deficiencies will be discussed in the Regional
enforcement letter.
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Indications on radiographs of stainless steel welding on low
prescure cafety related piping that had been accepted by the
contractor's QC staff as a "high-low" condition (a minor-
alignment deviation)has been identified as fissures in the
root pass.
Examination disclosed that the weld root was not
properly fused with the parent metal.
About 75% of the welds
exhibiting the "high-low" indications have been found to
contain the fissures.
All of these welds in safety related
cyntemn will be replaced.
While still under investigation,
the apparent . cauce of the problem appears to be moisture or
low level oxygen contamination in the purge gas.
The licensee
plans to cubmit a report to the Division of Compliance on
' thin problem.
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