[Federal Register Volume 75, Number 123 (Monday, June 28, 2010)]
[Pages 36700-36701]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-15626]



[Docket No. 50-289; NRC-2010-0221]

Exelon Generation Company, LLC; Three Mile Island Nuclear 
Station, Unit 1; Environmental Assessment and Finding of No Significant 

    The U.S. Nuclear Regulatory Commission (NRC) is considering 
issuance of an exemption from Title 10 of the Code of Federal 
Regulations (10 CFR) part 50, Appendix R, Section III.G, ``Fire 
Protection of Safe Shutdown Capability,'' for the use of an operator 
manual action in lieu of the requirements specified in Appendix R, 
Section III.G.2, for Renewed Facility Operating License No. DPR-50, 
issued to Exelon Generation Company, LLC (the licensee), for operation 
of Three Mile Island Nuclear Station, Unit 1 (TMI-1), located in 
Dauphin County, Pennsylvania. Therefore, as required by 10 CFR 51.21, 
the NRC performed an environmental assessment. Based on the results of 
the environmental assessment, the NRC is issuing a finding of no 
significant impact.

Environmental Assessment

Identification of the Proposed Action

    The proposed action would grant an exemption to the requirements of 
10 CFR part 50, appendix R, section III.G.2, based on an operator 
manual action contained in the licensee's Fire Hazards Analysis Report 
(FHAR), which is part of the TMI-1 Updated Final Safety Analysis 
Report. The licensee's FHAR requires that the identified operator 
manual action be performed outside of the control room to achieve safe 
shutdown following a fire in Fire Zone AB-FZ-6 (Demineralizer and ``A'' 
Motor Control Center Area). The licensee states that the manual action 
was subjected to a manual action feasibility review for TMI-1 that 
determined that the manual action is feasible and can be reliably 
    The proposed action is in accordance with the licensee's 
application dated March 3, 2009, as supplemented by letter dated March 
15, 2010 (Agencywide Documents Access and Management System (ADAMS) 
Accession Nos. ML090630134 and ML100750093, respectively).

The Need for the Proposed Action

    The proposed exemption modifies an existing exemption which was 
granted by letter dated December 30, 1986 (ADAMS Accession No. 
8701090216). The proposed modified exemption involves an operator 
manual action to open the supply breaker for the motor control center 
which powers valve MU-V-36, and then locally ensure that MU-V-36 is 
open. The proposed exemption specifies a reduced (40 minute) time frame 
to perform these actions as compared to one hour in the original 
exemption. The reduced timeframe is being specified because recent 
plant testing has shown that the backup air supply to seal injection 
valve MU-V-20 would only allow the valve to stay open for approximately 
75 minutes under the postulated conditions. With MU-V-20 closed, 
ensuring that valve MU-V-36 is open provides a minimum recirculation 
flow path for the makeup pumps. By maintaining a minimum recirculation 
flow path, the makeup pumps will not be susceptible to pump damage from 
operation in a ``deadheaded'' condition. The recent test results on MU-
V-20 necessitate a time reduction for the specified operator manual 
action to maintain sufficient time margin in order to prevent potential 
operation of the makeup pumps in a ``deadheaded'' condition.
    The proposed exemption is necessary because the crediting of 
operator manual actions to achieve and maintain hot shutdown is not 
addressed in 10 CFR part 50 appendix R, section III.G.2, and an 
exemption is therefore required in accordance with 10 CFR 50.12.

Environmental Impacts of the Proposed Action

    The NRC has completed its evaluation for the proposed action and 
concludes that the operator manual action addressed in the application 
is feasible and can be reliably performed. Further, the NRC concludes 
that there is sufficient defense-in-depth within the fire protection 
program to ensure that a redundant train necessary to achieve and 
maintain safe shutdown of the plant will remain free of fire damage in 
the event of a fire in the postulated area.
    The details of the staff's safety evaluation will be provided in 
the exemption that will be issued as part of the letter to the licensee 
approving the exemption to 10 CFR part 50, appendix R, section III.G.2.
    As described in the staff's safety evaluation that will be provided 
to the licensee with the exemption, the proposed action will not 
significantly increase the probability or consequences of accidents. 
Since the change being evaluated in this assessment involves only a 
change to the time allotted to accomplish a previously approved 
operator manual action, no changes are being made in the types of 
effluents that may be released off-site. Likewise, there is no 
significant increase in the amount of any effluent released off-site 
because the time change has no impact on any effluent release path or 
duration. There is no significant increase in occupational radiation 
exposure because, as described in the staff's safety evaluation, the 
areas of consideration for the operator manual action are expected to 
have dose rates of less than 10 millirem per hour. Since there is no 
impact to any radiological effluents or in-plant dose rates from the 
operator manual action time change, there is no impact to public 
radiation exposure. Therefore, there are no significant radiological 
environmental impacts associated with the proposed action.

[[Page 36701]]

    The operator manual action described in the proposed exemption 
involves ensuring recirculation flow within the plant makeup system 
such that it continues to operate as designed. It does not have any 
impact to water usage or impact plant systems that contribute to non-
radiological effluent releases from the plant. Therefore, the proposed 
action does not result in changes to land use or water use, or result 
in changes to the quality or quantity of non-radiological effluents. 
Likewise, no changes to the National Pollution Discharge Elimination 
System permit are needed and no effects on the aquatic or terrestrial 
habitat in the vicinity or the plant, or to threatened, endangered, or 
protected species under the Endangered Species Act, or impacts to 
essential fish habitat covered by the Magnuson-Stevens Act are 
expected. For the same reasons, there are no impacts to the air or 
ambient air quality, nor are there impacts to historical and cultural 
resources. With no impact of the proposed exemption beyond the site 
boundary, there would be no noticeable effect on socioeconomic 
conditions in the region. Therefore, no changes or different types of 
non-radiological environmental impacts are expected as a result of the 
proposed action.
    Accordingly, the NRC concludes that there are no significant 
environmental impacts associated with the proposed action.

Environmental Impacts of the Alternatives to the Proposed Action

    As an alternative to the proposed action, the NRC staff considered 
denial of the proposed action (i.e., the ``no-action'' alternative). 
Denial of the application would not result in a decrease in current 
environmental impacts. If the proposed action was denied, the licensee 
would have to perform plant modifications and/or reroute or wrap cables 
to achieve compliance. The environmental impacts of the proposed action 
and the alternative action are similar.

Alternative Use of Resources

    The action does not involve the use of any different resources than 
those previously considered in the Final Environmental Statement 
Related to the Operation of Three Mile Island Nuclear Station, Units 1 
and 2, NUREG-0552, dated December 1972, and Generic Environmental 
Impact Statement for License Renewal of Nuclear Plants (NUREG-1437, 
Supplement 37), dated June 2009.

Agencies and Persons Consulted

    In accordance with its stated policy, on March 29, 2010, the NRC 
staff consulted with the Pennsylvania State official, Dennis Dyckman, 
of the Pennsylvania State Department of Environmental Protection, 
regarding the environmental impact of the proposed action. The State 
official had no comments.

Finding of No Significant Impact

    On the basis of the environmental assessment, the NRC concludes 
that the proposed action will not have a significant effect on the 
quality of the human environment. Accordingly, the NRC has determined 
not to prepare an environmental impact statement for the proposed 
    For further details with respect to the proposed action, see the 
licensee's letter dated March 3, 2009, as supplemented on March 15, 
2010 (ADAMS Accession Nos. ML090630134 and ML100750093, respectively). 
Documents may be examined, and/or copied for a fee, at the NRC's Public 
Document Room (PDR), located at One White Flint North, Room O1 F21, 
11555 Rockville Pike (first floor), Rockville, Maryland. Publicly 
available records will be accessible electronically from the ADAMS 
Public Electronic Reading Room on the Internet at the NRC Web site, 
http://www.nrc.gov/reading-rm/adams.html. Persons who do not have 
access to ADAMS or who encounter problems in accessing the documents 
located in ADAMS should contact the NRC PDR Reference staff by 
telephone at 1-800-397-4209 or 301-415-4737, or send an e-mail to 
[email protected].

    Dated at Rockville, Maryland, this 15th day of June 2010.

    For the Nuclear Regulatory Commission.
Peter Bamford,
Project Manager, Plant Licensing Branch I-2, Division of Operating 
Reactor Licensing, Office of Nuclear Reactor Regulation.
[FR Doc. 2010-15626 Filed 6-25-10; 8:45 am]