[Federal Register Volume 62, Number 150 (Tuesday, August 5, 1997)]
[Notices]
[Pages 42146-42149]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-20546]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-309]
Maine Yankee Atomic Power Company; Maine Yankee Atomic Power
Station; Issuance of Director's Decision Under 10 CFR 2.206
Notice is hereby given that the Director, Office of Nuclear Reactor
Regulation, has taken action with regard to a Petition for action under
10 CFR 2.206 received from Mr. Patrick M. Sears (Petitioner), dated
August 19, 1996, and revised on April 14, 1997, with regard to the
Maine Yankee Atomic Power Station.
The Petitioner requested the NRC to (1) fine Maine Yankee Atomic
Power Company (MYAPCO) and Yankee Atomic Electric Company (YAEC) if
records regarding use of the computer code RELAP have not been kept in
accordance with YAEC's computer code quality assurance procedures and
(2) inspect all users of RELAP and fine those users not operating
within required computer code verification procedures.
The Director of the Office of Nuclear Reactor Regulation has
acknowledged parts (1) and (2) of the Petition. The reasons for this
decision are explained in the ``Director's Decision Pursuant to 10 CFR
2.206'' (DD-97-17), the complete text of which 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 for the Maine Yankee Atomic Power
Station located at the Wiscasset Public Library, High Street, P. O. Box
367, Wiscasset, Maine 04578.
A copy of this Decision will be filed with the Secretary of the
Commission for the Commission's review in accordance with 10 CFR
2.206(c). As provided by this regulation, this Decision will constitute
the final action of the Commission 25 days after the date of issuance
unless the Commission, on its own motion, institutes review of the
Decision within that time.
Dated at Rockville, Maryland, this 30th day of July 1997.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
Director's Decision Under 10 CFR 2.206
I. Introduction
On August 19, 1996, Patrick M. Sears (Petitioner) filed a Petition
with the U.S. Nuclear Regulatory Commission (NRC) pursuant to Section
2.206 of Title 10 of the Code of Federal Regulations (10 CFR 2.206).
Petitioner requested the NRC to (1) Fine Maine Yankee Atomic Power
Company (MYAPCO) and Yankee Atomic Electric Company (YAEC) if records
regarding use of the computer code RELAP5YA have not been kept in
accordance with YAEC's computer code quality assurance (QA) procedures,
and (2) inspect all users of RELAP and fine those users not operating
within required computer code verification procedures.
As the basis for these requests, the Petition states that (1) The
May 5, 1989, oral statement of Steve Nichols, then licensing supervisor
of MYAPCO, to Petitioner, then NRC Project Manager for Maine Yankee
Atomic Power Station (MYAPS), that RELAP5YA was ``operable'' and would
be used for subsequent reloads was false; (2) no computer code
inspections were performed by NRC before a 1992 inspection at YAEC by
Mr. Sears, and not again until 1995; (3) when Mr. Sears was in the
Vendor Inspection Branch, he was told not to do any more computer code
inspections; (4) RELAP is widely used; (5) RELAP has been shown to have
serious deficiencies; and (6) the RELAP problem is not confined to the
MYAPS but is endemic to the industry as a whole.
On September 24, 1996, Mr. William T. Russell, then Director of the
Office of
[[Page 42147]]
Nuclear Reactor Regulation, acknowledged receipt of the Petition. By
letter dated April 14, 1997, Petitioner supplemented his Petition by
correcting his characterization of Mr. Nichols' comment, substituting
the word ``operational'' for ``operable''.
II. Background
As a result of concerns regarding small-break loss-of-coolant
accident (SBLOCA) analyses of emergency core cooling systems (ECCS)
raised by the 1979 accident at Three Mile Island Unit 2, and pursuant
to 10 CFR 50.54(f), the NRC required licensees to submit revised,
documented SBLOCA analyses which were to meet the guidance provided in
NRC's ``Clarification of TMI Action Plan Requirements'' (NUREG-0737 or
TMI Action Plan), Item II.K.3.30. and II.K.3.31. In response to the
guidance of Item II.K.3.30, on January 14, 1983, Maine Yankee submitted
a report, YAEC-1300P, ``RELAP5YA: A Computer Program for Light Water
Reactor System Thermal-Hydraulic Analysis'' to the NRC. In January
1989, the NRC approved RELAP5YA for use by Maine Yankee as a 10 CFR
Part 50, Appendix K, evaluation model, acceptable to demonstrate
compliance with the requirements of 10 CFR 50.46, ``Acceptance criteria
for emergency core cooling systems for light water nuclear power
reactors.'' RELAP5YA is a generic, non-plant-specific LOCA computer
code for calculating ECCS performance over the small-break portion of
the break spectrum.
Item II.K.3.31 of the TMI Action Plan states that licensees are to
submit plant-specific calculations using the SBLOCA evaluation model
approved by the NRC pursuant to Item II.K.3.30. In response to TMI
Action Plan Item II.K.3.31, YAEC prepared for Maine Yankee a plant-
specific Appendix K, RELAP5YA SBLOCA evaluation model analysis and
prepared a report in June 1993 identified as YAEC-1868: ``Maine Yankee
Small Break LOCA Analysis.'' The SBLOCA analysis described in YAEC-1868
was used to prepare Core Performance Analysis Reports (CPARs) which
were submitted to the NRC as part of Maine Yankee's reload analyses for
Cycle 14 and Cycle 15 operations, and was the SBLOCA analysis of record
throughout Cycle 14 operations; it was not used during Cycle 15
operations because of the intervening January 3, 1996, ``Confirmatory
Order Suspending Authority for and Limiting Power Operation and
Containment Pressure (Effective Immediately), and Demand for
Information'' (Order).1 61 FR 735 (January 10, 1996).
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\1\ Among other things, the Order limited operation of MYAPS to
2440 MWt, pending NRC review and approval of a plant-specific SBLOCA
analysis which conforms to TMI Action Plan Items II.K.3.30 and
II.K.3.31 and which meets the requirements of 10 CFR 50.46.
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On December 4, 1995, the NRC received allegations that, among other
things, YAEC, acting as agent for the licensee, knowingly performed
inadequate analyses of the emergency core cooling system (ECCS) to
support two license amendment applications to increase the rated
thermal power at which MYAPS operates to 2630 MWt, and then to 2700
MWt. It was further alleged that YAEC management knew that the ECCS for
Maine Yankee, if evaluated in accordance with 10 CFR 50.46, using the
RELAP5YA SBLOCA evaluation model, did not meet licensing requirements.
In response to the allegations, NRC dispatched an Assessment Team
to YAEC headquarters between December 11 and 14, 1995, to examine,
among other things, SBLOCA analyses, especially the SBLOCA analysis
which supported the licensee's operating Cycle 15 reload application.
Based on the Assessment Team review, and a meeting held with the
licensee on December 18, 1995, the NRC staff issued its January 3,
1996, Order. The Order concluded, inter alia, that the licensee had not
demonstrated that computer code RELAP5YA would reliably calculate the
peak cladding temperature for all break sizes in the small-break LOCA
spectrum for Maine Yankee and that, for a variety of reasons, the
plant-specific application of RELAP5YA did not conform to the
requirements of 10 CFR 50.46 and thus was not acceptable for use by the
licensee. The Order required the licensee to submit a SBLOCA analysis
specific to Maine Yankee for operation at power levels up to 2700 MWt,
which must meet the requirements of 10 CFR 50.46, and which must
conform to the guidance of NUREG-0737, Items II.K.3.30 and 31, ``SBLOCA
Methods'' and ``Plant-specific Analysis,'' respectively, and NUREG-
0737, Item II.K.3.5, ``Automatic Trip of Reactor Coolant Pumps During
LOCA''. The Order suspended authority to operate Maine Yankee at 2700
MWt maximum power and limited power to 2440 MWt, pending NRC review and
approval of the required SBLOCA analysis. MYAPCO submitted the required
SBLOCA analysis specific to Maine Yankee on April 25, 1996, and the NRC
staff is currently reviewing it.
The NRC also initiated an investigation by the NRC Office of
Investigations (OI) to examine possible wrongdoing. The NRC staff is
currently reviewing the results of that investigation.
III. DISCUSSION
A. Do MYAPCo and Other NRC Licensees Who Use RELAP Operate Within
Required Computer Code Verification Procedures?
Petitioner requests that the NRC inspect all users of RELAP and
fine those users not operating within required computer code
verification procedures. The staff presumes that the phrase ``required
computer code verification procedures,'' as used by Petitioner, means
the conditions, if any, of the NRC's approval of the computer code, as
well as the licensee or vendor quality assurance (QA) procedures
pursuant to 10 CFR part 50, Appendix B.
There are many vintages of RELAP, which was developed by Idaho
National Engineering Laboratory, such as RELAP4, RELAP5/MOD1, RELAP5/
MOD2, and RELAP5/MOD3 (higher suffix numbers indicate more current
vintages). Major improvements were made in each new vintage, including
the use of more sophisticated modeling of two-phase flow. For example,
RELAP5/MOD1 has a ``mixture'' model with five governing equations,
whereas RELAP5/MOD2 has a full two-fluid treatment with six equations.
Each vintage of RELAP has many versions, representing primarily
modifications in supporting models on constitutive relationships and
corrections of errors. Idaho National Engineering Laboratory maintains
a reporting system for problems discovered by users of the code, which
are prioritized and referred to the code development staff for
resolution. Therefore, it cannot be assumed that a problem with a
particular RELAP vintage or version also exists in other RELAP vintages
or versions.
Vendors or licensees who use RELAP codes to support license
applications normally take a specific vintage or version of RELAP and
create their own variations by making modifications and adding certain
features, such as those required by 10 CFR part 50, Appendix K. The
RELAP codes used by different vendors and licensees are not necessarily
developed from the same versions or vintages of RELAP. For example, the
RELAP5YA code used by YAEC for Maine Yankee SBLOCA analysis was derived
from RELAP5/MOD1, while most other RELAP codes used for the ECCS
analyses of NRC-licensed nuclear plants were derived
[[Page 42148]]
from different vintages, namely, RELAP4 or RELAP5/MOD2.
Before a vendor-modified or licensee-modified RELAP code is used
for licensing applications, it must be reviewed and approved by the
staff. The staff's review and approval will require, among other
things, benchmark comparison of the code's predictions against
experimental test data. In many cases, the staff's approval of a
licensing RELAP code imposes conditions or restrictions for application
of the code to ensure that licensing calculations are acceptably
conservative, in accordance with the requirements of 10 CFR 50.46 and
Appendix K to 10 CFR part 50. The implementation by a licensee or
vendor of an approved emergency core cooling system (ECCS) code is
controlled by the licensee or vendor's own quality assurance programs
in accordance with Appendix B to 10 CFR part 50.
In view of the above, it cannot be presumed that all other vintages
of RELAP codes used by the industry have the same deficiencies as those
experienced by Maine Yankee with its particular vintage of RELAP, that
is RELAP5/MOD1. Two NRC licensees other than Maine Yankee, however,
used the RELAP5/MOD1 vintage, that is, Yankee Rowe Nuclear Power
Station and Vermont Yankee Nuclear Power Station. Yankee Rowe Nuclear
Power Station has been permanently shut down for decommissioning since
October 1, 1991. In May 1996, the NRC staff conducted an ECCS code and
analysis inspection, and in June 1996, a special inspection of Vermont
Yankee. As a result, the NRC issued a Notice of Violation and Proposed
Imposition of Civil Penalty--$50,000 (EA 96-210) on August 23, 1996,
for the licensee's failure to assume a specific failure scenario in the
LOCA analysis. In that enforcement action, the NRC staff also concluded
that Vermont Yankee's corrective actions were prompt and comprehensive.
With respect to Maine Yankee, the NRC staff has examined MYAPCO's use
of RELAP5YA through the Assessment Team review and the OI
investigation. The staff's evaluation of Maine Yankee's use of RELAP5YA
is ongoing with regard to any violations of NRC requirements, including
10 CFR 50.46. The staff will keep Petitioner informed by providing
Petitioner with copies of publicly available inspection reports and
enforcement actions.
Petitioner, nonetheless, correctly points out that the NRC staff
should conduct ECCS code and analysis inspections more frequently. In
February 1997, the staff's Maine Yankee Lessons Learned Task Group
provided its report to the Commission, ``Report of the Maine Yankee
Lessons Learned Task Group'' (December 5, 1996), Attachment 1 to SECY-
97-042, ``Response to OIG Event Inquiry Regarding Maine Yankee''
(February 18, 1997). The Task Group identified a need to place
additional emphasis on (1) audits and inspections of implementation by
licensees and vendors of their ECCS codes and methodologies, not
limited to the various RELAP codes, and (2) verification of the
conformance by licensees and vendors with the conditions specified in
the NRC staff's Safety Evaluation Reports as a basis for determining
whether codes and methodologies conform with NRC requirements. The Task
Group also addressed inspections pursuant to the Core Performance
Action Plan, performed to assess the impact of reload core design
activities on plant safety. Licensees or vendors found to be in
violation of NRC regulations will be subject to enforcement actions.
As explained above, there is no basis to conclude that the problems
identified with the RELAP5/MOD1 vintage ECCS code used by Maine Yankee
are or may be present in the different RELAP code vintages at other
NRC-licensed plants. Additionally, the two other users of the RELAP5/
MOD1 code vintage have either been inspected (Vermont Yankee) or are
permanently shut down (Yankee Rowe). Nevertheless, the NRC will conduct
computer code inspections of selected NRC licensees and vendors, not
limited to users of RELAP, as explained above.
In view of the above, Petitioner's request to inspect all users of
RELAP and to fine those users not operating within required computer
code verification procedures is granted in part, since some users of
RELAP will be included in forthcoming computer code inspections and
since Maine Yankee and Vermont Yankee have already been inspected.
B. Have MYAPCO and YAEC Kept Records of the Use of the RELAP ECCS
Computer Code in Accordance with YAEC's Computer Code Quality Assurance
Procedures?
Petitioner requests that the NRC fine MYAPCO and YAEC if records
regarding use of the computer code RELAP5YA have not been kept in
accordance with YAEC's computer code quality assurance (QA) procedures.
The NRC staff's review of the application of RELAP5YA for Maine Yankee
between December 11 and 14, 1995, focused on the adequacy of the
RELAP5YA SBLOCA analysis to support operation of Maine Yankee during
Cycle 15. In particular, the staff evaluated conformance of the code to
SER conditions and compliance of the ECCS evaluation model with
regulatory requirements. Although the staff's review did not focus on
record keeping requirements, the staff did not identify instances in
which the appropriate records had not been kept. The staff is
continuing its evaluation of RELAP5YA for compliance with other NRC
requirements.
Siemens Power Corporation (SPC) has prepared a plant-specific
SBLOCA ECCS evaluation model for Maine Yankee, which has been submitted
by Maine Yankee in response to the January 3, 1996, Order. The
evaluation model is based on SPC's ANF-RELAP SBLOCA methodology, which
was originally approved by the NRC in 1989, with further modifications
approved by the NRC in 1994. Between February 10, 1997 and April 4,
1997, the staff conducted a four-week QA inspection of SPC. The
inspection included a comprehensive review of documentation associated
with SPC's LBLOCA and SBLOCA ECCS evaluation models, including the
approved ANF-RELAP SBLOCA methodology. The staff's findings associated
with ANF-RELAP will be documented in the inspection report, which will
be issued by the NRC in the near future. A copy of the inspection
report will be provided to Petitioner when it is publicly available. In
addition, the NRC staff is currently performing a detailed technical
review of the plant-specific ANF-RELAP ECCS evaluation model prepared
by SPC for Maine Yankee, and submitted by Maine Yankee. The staff's
evaluation of the plant-specific evaluation model will be documented in
a Safety Evaluation Report (SER) when completed. The staff concludes
that these activities respond directly to the issues raised by
Petitioner.
In view of the above, the Petitioner's request for a QA inspection
of Maine Yankee's and YAEC's use of RELAP is granted in part, by virtue
of the staff's previous and current inspection and review activities.
Additionally, the staff will keep Petitioner informed by providing
Petitioner with publicly available inspection reports, enforcement
actions, and other documents as appropriate.
IV. Conclusion
As explained above, Petitioner's request to inspect all users of
RELAP and fine those users not operating within required computer code
verification procedures is granted in part. Petitioner's request to
fine MYAPCO and YAEC if records regarding use of the computer code
RELAP have not been kept in
[[Page 42149]]
accordance with YAEC's computer code quality assurance procedures is
also granted in part.
A copy of this Director's Decision will be filed with the Secretary
of the Commission for Commission review in accordance with 10 CFR
2.206(c) of the Commission's regulations. As provided by this
regulation, this Director's 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 within that time.
Dated at Rockville, Maryland, this 30th day of July 1997.
For the Nuclear Regulatory Commission.
Samuel J. Collins,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 97-20546 Filed 8-4-97; 8:45 am]
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