[Federal Register Volume 61, Number 229 (Tuesday, November 26, 1996)]
[Notices]
[Pages 60124-60126]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-30155]


-----------------------------------------------------------------------

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 Acting Director, Office of Nuclear 
Reactor Regulation, has acted on a Petition for action under 10 CFR 
2.206 received from Ms. Anne D. Burt, on behalf of Friends of the 
Coast--Opposing Nuclear Pollution, dated January 20, 1996, for the 
Maine Yankee Atomic Power Station.
    The Petition requests that the Commission take expedited action to 
(1) suspend the operating license of Maine Yankee pending resolution of 
the Petition; (2) examine and test by plug sampling--or other methods 
approved by the American Society of Mechanical Engineers--all large 
piping welds that may have been susceptible to micro-fissures at the 
time of construction; (3) reanalyze the Maine Yankee containment as one 
located in an area where seismic risk is not ``low''; (4) reduce the 
licensed operating capacity of Maine Yankee to a level consistent with 
a flawed containment and/or flawed reactor coolant piping welds; (5) 
hold an informal public hearing in the area of the plant regarding the 
Petition; and (6) place the Petitioner on service and mailing lists 
relevant to the group's interests in safety at Maine Yankee and 
intention to participate in all public forums opened by the Nuclear 
Regulatory Commission (NRC).
    By letter dated May 13, 1996, the Director, Office of Nuclear 
Reactor Regulation (NRR), NRC, acknowledged the NRC's receipt of the 
Petition, and, for the reasons stated in the letter, denied 
Petitioner's request for immediate action suspending the operating 
license or reducing the licensed operating capacity of Maine Yankee 
(Requests 1 and, in part, 4). In addition, for reasons stated in the 
May 13, 1996, letter, the Director denied the Petitioner's request for 
an informal hearing (Request 5). The Director also stated in the May 
13, 1996, letter that Petitioner's request that the NRC place 
Petitioner on service and mailing lists relevant to its interests in 
safety at Maine Yankee and its intention to participate in all public 
forums opened by the NRC (Request 6) was moot, as Petitioner's attorney 
had already been added to the Maine Yankee service list.
    The Acting Director of the Office of Nuclear Reactor Regulation has 
now determined that no basis exists for taking any action in response 
to Requests 2, 3, and 4 of the Petition dated January 20, 1996. 
Accordingly, Requests 2, 3, and 4 have been denied for the reasons 
stated in the ``Director's Decision Under 10 CFR 2.206'' (DD-96-20), 
the complete text of which follows this notice and which is available 
for public inspection at the Commission's Public Document Room, the 
Gelman Building, 2120 L Street, N.W., Washington, D.C. 20555, and at 
the local public document room 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 for the Commission's review 
in accordance with 10 CFR 2.206. As provided by the regulation, the 
Decision will constitute the final action of the Commission 25 days 
after the date of issuance of the Decision unless the Commission on its 
own motion institutes a review of the Decision within that time.

    Dated at Rockville, Maryland, this 20th day of November 1996.

    For the Nuclear Regulatory Commission.
Frank J. Miraglia,
Acting Director, Office of Nuclear Reactor Regulation.

I. Introduction

    By letter dated January 20, 1996, Ms. Anne D. Burt filed a Petition 
with the U.S. Nuclear Regulatory Commission (NRC), pursuant to 10 CFR 
2.206, on behalf of the Friends of the Coast--

[[Page 60125]]

Opposing Nuclear Pollution (the Petitioner) requesting that actions be 
taken regarding the Maine Yankee Atomic Power Station (Maine Yankee), 
operated by the Maine Yankee Atomic Power Company (the licensee). The 
Petition requests that the Commission take expedited action to (1) 
suspend the operating license of Maine Yankee pending resolution of the 
Petition; (2) examine and test by plug sampling--or other methods 
approved by the American Society of Mechanical Engineers--all large 
piping welds that may have been susceptible to micro-fissures at the 
time of construction; (3) reanalyze the Maine Yankee containment as one 
located in an area where seismic risk is not ``low''; (4) reduce the 
licensed operating capacity of Maine Yankee to a level consistent with 
a flawed containment and/or flawed reactor coolant piping welds; (5) 
hold an informal public hearing in the area of the plant regarding the 
Petition; and (6) place the Petitioner on service and mailing lists 
relevant to the group's interests in safety at Maine Yankee and 
intention to participate in all public forums opened by the NRC.
    By letter dated May 13, 1996, the Director, Office of Nuclear 
Reactor Regulation (NRR), NRC, acknowledged the NRC's receipt of the 
Petition, and, for the reasons stated in the letter, denied 
Petitioner's request for immediate action suspending the operating 
license or reducing the licensed operating capacity of Maine Yankee 
(Requests 1 and, in part, 4). In addition, for reasons stated in the 
May 13, 1996, letter, the Director denied the Petitioner's request for 
an informal hearing (Request 5). The Director also stated in the May 
13, 1996, letter that the request that the NRC place Petitioner on 
service and mailing lists relevant to its interests in safety at Maine 
Yankee and its intention to participate in all public forums opened by 
the NRC (Request 6) was moot, as Petitioner's attorney had already been 
added to the Maine Yankee service list. In addition, the Petitioner was 
informed that NRC would review the Petition in accordance with 10 CFR 
2.206 and issue a final decision within a reasonable time.
    The remaining specific requests for NRC action in the Petition 
dated January 20, 1996, i.e., Requests 2, 3, and 4 identified above, 
and the issues that Petitioner raised as their bases, are addressed in 
this decision. For the reasons set forth below, Petitioner's remaining 
requests for action pursuant to 10 CFR 2.206 are denied.

II. Discussion

    The NRC staff has conducted a thorough evaluation of each of the 
two safety-related issues raised in the Petition regarding the adequacy 
of the containment and reactor coolant welds. Each of the issues is 
addressed below.

a. Adequacy of Containment Design at or Above Originally Authorized 
Power Level

    The Petitioner asserts that the containment is inadequate for 
operation at any power in excess of that authorized in the original 
license, and may be inadequate for the originally licensed power level 
because of insupportable original design acceptance criteria in that 
the Maine Yankee containment was designed and constructed without 
diagonal rods. The Petitioner states that

    The Atomic Energy Commission staff recommended to the commission 
that a license amendment permitting this type of construction be 
allowed, ``* * * for this plant and this plant only due to low 
seismic risk.'' Early in 1979 the MYAPS was shaken by an earthquake 
of 4.2 magnitude and epicentered less than ten miles from the plant 
site. The NRC then ordered the shutdown of five nuclear power 
stations including MYAPS until piping and piping supports could be 
seismically qualified * * *

    The Petitioner also states that there is no public record, however, 
that NRC reevaluated what Petitioner asserts is a marginally acceptable 
containment design at Maine Yankee before it granted license amendments 
to operate at increased power.
    The Maine Yankee containment is a reinforced concrete structure. 
The original NRC operating license review determined that the seismic 
and thermal-hydraulic design of Maine Yankee's containment structure is 
adequate. (The construction permit for Maine Yankee was issued on 
October 21, 1968, and the operating license was issued on September 15, 
1972.) With its Petition of January 20, 1996, the Petitioner enclosed 
an NRC letter of January 22, 1971, in which the staff asked the 
licensee to submit additional information related to seismic shear 
stress, given that there are no diagonal seismic shear reinforcements 
in the containment wall. Low seismicity of the site was not a factor in 
the staff's acceptance of the Maine Yankee containment design without 
diagonal seismic reinforcement bars. As described below, acceptance by 
the staff of the adequacy of the seismic design was based on the 
results of stress analyses.
    The earthquake for which Maine Yankee was originally designed--
termed a Safe Shutdown Earthquake (SSE)--is based on a Housner design 
response spectrum with a zero period peak horizontal ground 
acceleration of 0.10g. The five plant shutdown that was ordered on 
March 13, 1979, was triggered by a finding of an error in a piping 
computer program, which led to the issuance of IE Bulletin No. 79-07, 
``Piping Stress Analysis of Safety-Related Piping'' on April 14, 1979. 
The earthquakes that occurred near the plant site starting on April 18, 
1979, at 02 hours and 34 minutes universal time, were not a factor in 
the five plant shutdown that was ordered on March 13, 1979. As a 
consequence of the sequence of earthquakes that occurred near the plant 
in April 1979 and the occurrence of the January 9, 1982, magnitude 5\3/
4\ earthquake in New Brunswick, Canada, the licensee undertook a 
seismic analysis program. This program included analyses and upgrading 
of certain plant components and a reevaluation of the seismic hazard. 
Thus, the results from the seismic analyses and upgrading program were 
instrumental in the staff's conclusion that the existing seismic design 
for Maine Yankee remained adequate. However, following its review of 
the seismic hazard reevaluation, the NRC staff determined that the 
appropriate characterization of the ground motion for any future 
analysis of the plant is a high-frequency peak ground acceleration of 
0.18 g anchoring the response spectrum obtained from NUREG/CR-0098, 
``Development of Criteria for Seismic Review of Selected Nuclear Power 
Plants,'' using the 50th percentile amplification factors.
    Subsequently, in 1986, the Maine Yankee Plant underwent a seismic 
margin assessment program. The review-level earthquake used in the 
seismic margin assessment had a peak ground acceleration of 0.3g, which 
is much greater than the peak ground acceleration of the SSE. The 
seismic safety margin program included a review of the entire plant 
including analysis and upgrading of certain plant components, such as 
Main Control Board, Control Room Auxiliary Cabinets, Service Water 
Piping Support and others. As a result of this reassessment, it was 
established that, with the upgrades implemented at the plant, the Maine 
Yankee Plant can be safely shut down during an earthquake with a peak 
ground acceleration of 0.27g.
    In its report ``Seismic Margin Review of the Maine Yankee Atomic 
Power Station'' (NUREG/CR-4826, Vol. 2,

[[Page 60126]]

dated March 1987), the NRC staff also concluded that the overall 
seismic margin of the plant, including the containment, was well above 
the 0.18g value and, therefore, no upgrading of the seismic design was 
considered necessary. Further, in the staff report ``An Approach to the 
Quantification of Seismic Margins in Nuclear Power Plants'' (NUREG/CR-
4334, dated August 1985), it is also noted that prestressed and 
reinforced concrete containment structures have a large seismic margin 
above the SSE level earthquake.
    Additionally, numerous tests and studies conducted since the 
operating license review of the Maine Yankee Plant, specifically on 
shear stress in biaxially cracked reinforced concrete without diagonal 
reinforcement bars, have led to the acceptance of specified allowable 
shear stress by the American Society of Mechanical Engineers (ASME) 
Boiler and Pressure Vessel Code (Code), Section III, Division 2, CC-
3421.5, for reinforced-concrete containment structures. An analysis of 
the Maine Yankee containment structure was conducted in December 1984 
by the licensee and submitted on the Docket as an attachment to letter 
MN-85-27, dated February 5, 1985. The results of the study indicate 
that the controlling peak ground acceleration value is 0.39g for the 
ASME Code allowable tangential shear stress caused by the SSE loading 
in combination with design-basis internal pressure and dead loads. This 
provides additional confidence on the ruggedness of the Maine Yankee 
containment.
    Based on the above, with regard to the Petitioner's concern about 
the adequacy of the Maine Yankee containment structural design for 
earthquakes (seismic), the staff concludes that the Maine Yankee 
containment is satisfactory and has adequate margin. The NRC staff has 
determined that the design of the Maine Yankee containment structure 
without diagonal reinforcement bars is supported by analysis and poses 
no undue risk to public health and safety. Accordingly, Petitioner's 
requests for NRC action based on the seismic design of the containment 
are denied.

b. Microfissuring of Low-Ferrite Stainless Steel Weldments

    The Petitioner asserts that the Maine Yankee emergency core cooling 
system (ECCS), reactor coolant piping, and other large piping have not 
been adequately analyzed for materials degradation to ensure integrity 
at power operation in excess of the originally licensed power level or 
under accident conditions. The Petitioner states further that the 
Atomic Energy Commission's concern with ``microfissures'' in reactor 
coolant system welds led to the appointment of a task force, and 
prompted studies and reports in 1971 (before heightened awareness of 
embrittlement phenomena) that concluded that the microfissures would 
not propagate or grow under foreseeable conditions. The Petitioner 
asserts that large pipe welds next to the reactor vessel have endured 
23 years of corrosion, stress, vibration, and radiation and may fail, 
initiating a loss-of-coolant accident, or may be subject to thermal 
shock failure initiated by use of the ECCS.
    In a safety evaluation dated February 25, 1972, the NRC staff 
concluded that the low-ferrite stainless steel weldments in large 
piping at Maine Yankee are acceptable because the micro-fissures of the 
type and density found in the low-ferrite stainless steel weldments of 
the Maine Yankee facility do not significantly impair the strength and 
capability of the welds, and that removal of the welds and rewelding 
could introduce other problems of greater safety significance than 
those resulting from the presence of microfissures. This evaluation was 
based on information provided by Battelle Columbus Laboratories, Stone 
and Webster Engineering Corporation, and Dr. Ernest F. Nippes of 
Rensselaer Polytechnic Institute. Furthermore, the Maine Yankee reactor 
vessel meets the requirements of 10 CFR 50.61, ``Fracture Toughness 
Requirements for Protection Against Pressurized Thermal Shock.'' In 
addition, the large diameter pipe welds attached to, or next to, the 
reactor vessel do not receive sufficient radiation to cause 
embrittlement. Finally, Type 316 stainless steel weld material, in 
which the microfissures were discovered, is resistant to corrosion in a 
PWR coolant environment, and the vibratory loads are insufficient to be 
a concern for large diameter piping.
    In a letter to the Petitioner dated May 13, 1996, the staff stated 
that in order to determine if there is any long-term safety 
significance of the microfissures, the staff will review the inservice 
inspection results for the welds identified as being susceptible to 
microfissures. The staff has now completed its review of the inservice 
inspection tests results for welds susceptible to microfissures. The 
staff's review confirmed that no unacceptable indications have been 
observed during inservice inspection. In addition, pressure tests have 
not identified any leakage. These tests indicate that 23 years of plant 
operation have not caused the microfissures to grow to a size 
detectable by inservice inspection or through-wall leakage. Plug sample 
testing was performed by Battelle, Columbus Laboratories, on the 
primary coolant system low-ferrite welds (Reference: Battelle's report 
dated September 17, 1971, which was transmitted by the licensee to the 
NRC by letter dated September 21, 1971). As part of the inservice 
inspection program in accordance with 10 CFR 50.55a(g), the licensee 
has been performing and continues to perform ASME Code inspections of 
large piping welds that may have been susceptible to microfissures at 
the time of construction. Additional plug sample testing would not 
yield any pertinent additional information and is not needed.
    On the basis of the above analyses, inservice inspection, and 
pressure test results, microfissures are not considered a long-term 
safety-significant issue for Maine Yankee. Accordingly, the 
Petitioner's remaining requests for NRC action based on asserted 
microfissures in large piping welds is denied.

III. Conclusion

    As explained above, and as requested by the Petitioner, the staff 
examined the adequacy of containment design and susceptibility of welds 
to microfissures. For the reasons stated above, no basis exists for 
taking any further action in response to the Petition. Accordingly, no 
action pursuant to 10 CFR 2.206 is being taken in this matter.
    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 a review of the Decision within that time.

    Dated at Rockville, Maryland, this 20th day of November 1996.

    For the Nuclear Regulatory Commission.
Frank J. Miraglia,
Acting Director, Office of Nuclear Reactor Regulation.
[FR Doc. 96-30155 Filed 11-25-96; 8:45 am]
BILLING CODE 7590-01-P