[Federal Register Volume 63, Number 55 (Monday, March 23, 1998)]
[Notices]
[Pages 13884-13886]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-7427]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-443]
North Atlantic Energy Service Corporation Seabrook Station, Unit
No. 1; Issuance of Director's Decision Under 10 CFR 2.206
Notice is hereby given that the Director, Office of Nuclear Reactor
Regulation (NRR), has taken action with regard to a Petition dated
December 18, 1997, submitted by Ms. Jane Doughty on behalf of The
Seacoast Anti-Pollution League. The Petition requests that the
operating license for Seabrook Station be suspended until such time as
a thorough root cause analysis of the reasons underlying the
development of leaks in piping of the ``B'' train of the
[[Page 13885]]
residual heat removal (RHR) system is conducted. The leakage was
reported by North Atlantic Energy Services Corporation, the Licensee
for Seabrook Station, on December 5, 1997. The Petition asserts that
there have been past allegations of improper welding practices and
documentation, and installation of substandard piping at Seabrook
Station and requests that the investigations of the RHR system pipe
leakage include findings related to these past allegations.
The Director of NRR has denied the Petitioner's request to suspend
the operating license of the Seabrook Station. In the Director's
Decision Pursuant to 10 CFR 2.206 (DD-98-03), the staff of the U.S.
Nuclear Regulatory Commission has discussed each of the concerns raised
by the Petitioner and found that the cause of the leaks in the piping
in the ``B'' train of the RHR system was the result of service-induced
degradation. There were no deficiencies identified in the fabrication
of the original piping or welds that would have generic implications
for other plant systems and that would require the operating license of
the facility to be suspended. The complete text of the Decision follows
this notice and is available for public inspection at the Commission's
Public Document Room, the Gelman Building, 2120 L Street, NW.,
Washington, DC, and at the local public document room located at the
Exeter Public Library, Founders Park, Exeter, New Hampshire 03833.
A copy of the Decision will be filed with the Secretary of the
Commission for the Commission's review in accordance with 10 CFR
2.206(c) of the Commission's regulations. As provided for by this
regulation, the Decision will constitute the final action of the
Commission 25 days after the date of issuance, unless the Commission,
on its own motion, institutes a review of the decision in that time.
Dated at Rockville, Maryland, this 17th day of March 1998.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
Director's Decision Pursuant to 10 CFR 2.206
I. Introduction
On December 18, 1997, Ms. Jane Doughty submitted a Petition to the
Executive Director for Operations of the U.S. Nuclear Regulatory
Commission (NRC) on behalf of The Seacoast Anti-Pollution League
requesting that the operating license for Seabrook Station be suspended
until such time as a thorough root cause analysis of the reasons
underlying the development of leaks in piping of the ``B'' train of the
residual heat removal (RHR) system is conducted. The leakage was
reported by North Atlantic Energy Service Corporation, the Licensee for
Seabrook Station, on December 5, 1997.
The Petition requested that the restart of the Seabrook Station
following repairs to the RHR system piping be delayed until all such
actions requested by the Petition are taken. On January 15, 1998, the
NRC informed the Petitioner in an acknowledgment letter that on the
basis of the Licensee's preliminary analysis of the cause of the pipe
leakage, the NRC staff found no reason to prevent the plant from
restarting. The acknowledgment letter further informed the Petitioner
that her Petition had been referred to the Office of Nuclear Reactor
Regulation pursuant to 10 CFR 2.206 for preparation of a Director's
Decision and that action would be taken within a reasonable time
regarding the specific concerns raised in the Petition.
II. Discussion
The Petition requests, in part, ``that the operating license for
the Seabrook Station Nuclear Power Plant [Seabrook Station] be
suspended until such time as a thorough root cause analysis of the
reasons underlying the development of leaks. . .in piping in the ``B''
train of the Residual Heat Removal (RHR) system is conducted, including
but not limited to a review of documentation associated with welds in
the area of the leakage and their associated inspection documentation,
a review of the qualification of the piping involved, and a review of
the procedures for ongoing assurance of weld and piping quality at the
plant.'' The Petition asserts that there have been past allegations of
improper welding practices and documentation, and installation of
substandard piping at Seabrook Station and requests that the
investigations of the RHR system pipe leakage include findings related
to these past allegations and the implications of this incident for
other plant systems. Each of these concerns is addressed below.
A. Root Cause Analysis
The Licensee has concluded that the cause of the RHR piping leak
was chloride-induced transgranular stress-corrosion cracking initiated
from the outside diameter of the pipe. The stress-corrosion cracking
was the result of repeated wettings and dryings of a protective
covering attached to the pipe with red duct tape during construction of
the facility. The covering was installed to prevent other welding
activities from damaging the pipe after it was installed and should
have been removed prior to placing the RHR system in service. After
being wetted the protective covering and tape leached chlorides,
allowing the chlorides to concentrate on the outer surface of the pipe
over time. The chlorides provided an agent to initiate stress-corrosion
cracking of the stainless steel pipe material. The Licensee has
conducted an inspection of accessible areas both inside and outside
containment for similar instances of unapproved materials being
attached to stainless steel piping and none were found.
The NRC staff has reviewed the Licensee's conclusions, including
observations of the failed pipe section and a review of the relevant
metallurgical and chemistry reports. The NRC staff found that the
metallurgical and chemistry reports provide an adequate basis for the
Licensee's conclusion that the leaks were the result of stress-
corrosion cracking initiated from the outside diameter of the pipe that
progressed through the pipe wall to the inside surface. The NRC staff's
findings are documented in Inspection Report 50/443/97-08.
B. Review of Weld Documentation
The Licensee conducted a review of the original radiographs of the
affected welds and found no anomalies in the weld or the base metal.
This finding indicates that the cause of the leakage was the result of
service-induced conditions and not a weld or piping defect originating
from the original construction.
The NRC staff's review of the radiographs confirmed that there were
no adverse construction weld quality problems, such as cracks,
porosity, or weld slag shown on the pipe weld radiographs in the
vicinity of the leaks or on the similar welds on the ``A'' train of the
RHR system. No defective welds were found. The NRC staff's findings are
documented in Inspection Report 50-443/97-08.
C. Review of Pipe Qualification
The Licensee reviewed the original material test reports and
purchase specification documentation for the affected piping sections.
Chemical analysis of the removed piping sections confirmed that the
material met the specification for SA312 Type 304 stainless steel pipe.
The NRC staff's review of the chemistry analysis and
photomicrographs showed the pipe material to be Type 304 stainless
steel. The NRC staff's findings are
[[Page 13886]]
documented in Inspection Report 50-443/97-08.
D. Review of the Procedures for Ongoing Assurance of Weld and Pipe
Quality
In conjunction with the most recent refueling outage at Seabrook
Station, the NRC staff conducted a review of the Licensee's American
Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME
Code) Section XI inservice inspection program plan for ensuring
structural and leaktight integrity of systems important to safety. The
NRC inspector found the implementation of all elements of the program
to be on schedule and in accordance with the rules of Section XI of the
ASME Code.
The NRC inspector observed and/or reviewed the results of inservice
inspections conducted by the Licensee on plant equipment, including
several piping welds. The NRC inspector found that the inspections were
performed in accordance with the rules of Section XI of the ASME Code
and NRC regulations. The NRC staff's findings are documented in
Inspection Report 50-443/97-03.
E. Review of Past Allegations of Improper Welding Practices
On March 27, 1990, the NRC's Executive Director for Operations
established an independent review team to conduct an assessment of the
adequacy of the construction welding and nondestructive examination
(NDE) practices at Seabrook Station. The team's findings are documented
in NUREG-1425, ``Welding and Nondestructive Examination Issues at
Seabrook Nuclear Station.'' The independent review team concluded that
the pipe welding and NDE programs were generally consistent with
applicable codes and NRC requirements and resulted in technically
acceptable pipe welds.
In investigating the leaks in the ``B'' train of the RHR system
reported on December 5, 1997, the NRC staff did not identify any
factors that would provide a basis for disagreeing with the Licensee's
conclusion that the cause of the leakage was the result of service-
induced conditions and not a weld or piping defect originating from the
original construction. Likewise, the investigation of this issue did
not provide any information that would question the validity of NUREG-
1425. Therefore, no further action by the NRC staff is warranted with
respect to the past allegations of improper welding practices and
substandard quality piping in response to the Petitioner's request.
F. Implications for Other Plant Systems
The Licensee has concluded that the cause of the leakage in the
``B'' train of the RHR system reported on December 5, 1997, was the
result of a service-induced condition and not a defect originating from
the original construction. The NRC staff has reviewed the Licensee's
activities related to the root cause analysis and subsequent repair in
response to the RHR system pipe leakage. The NRC staff found no
evidence of improper welding practices or substandard piping that
contributed to the RHR system pipe leakage and that would result in
generic implications to other plant systems.
III. Conclusion
The NRC staff has reviewed the information submitted by the
Petitioner, and the Petitioner's request to suspend the operating
license of the Seabrook Station is denied. As described above, the NRC
staff has found that the cause of the leaks in the piping in the ``B''
train of the RHR system was the result of service-induced degradation.
There were no deficiencies identified in the fabrication of the
original piping or welds that would have generic implications for other
plant systems and that would require the operating license of the
facility to be suspended.
As provided in 10 CFR 2.206(c), a copy of this Decision will be
filed with the Secretary of the Commission for the Commission's review.
This Decision will constitute the final action of the Commission 25
days after issuance, unless the Commission, on its own motion,
institutes review of the Decision in that time.
Dated at Rockville, Maryland, this 17th day of March 1998.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 98-7427 Filed 3-20-98; 8:45 am]
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