5.4 Power and Utilities — Nuclear
The U.S. Nuclear Regulatory Commission (NRC) defines decommissioning as permanently removing a nuclear facility from service and reducing
radioactive material on the licensed site to levels that permit termination of the NRC license. Legal
obligations associated with the decommissioning of a nuclear power plant generally are within the scope
of ASC 410-20.
5.4.1 Nuclear Power Plant Decommissioning
Decommissioning involves removing the spent nuclear fuel (i.e., the fuel that has been in the reactor vessel),
dismantling any systems or components containing activated material (such as the reactor vessel and
primary loop), and cleaning up or dismantling contaminated materials from the facility. All activated
materials generally have to be removed from the site and shipped to a waste processing, storage, or
disposal facility.
The legal obligation associated with the decommissioning of a nuclear power
plant arises from the regulations established by the NRC. Before a nuclear power
plant begins operations, the NRC requires the licensee to establish or obtain a
financial mechanism, such as a trust fund or a guarantee from its parent
company, to ensure that there will be sufficient money to cover the cost for the
ultimate decommissioning of the facility. The minimum decommissioning funding
required by the NRC reflects only the efforts necessary to terminate the NRC
license, which is commonly known as the “Part 50 license.”1 This license is not terminated until the licensee has completed all
activities included in the approved license termination plan (LTP). Other
activities related to facility deactivation and site closure, including
operation of the spent fuel storage pool, construction and operation of an
independent spent fuel storage installation (ISFSI), demolition of
decontaminated structures, and site restoration activities after residual
radioactivity has been removed, are not included in the NRC definition of
decommissioning. However, costs for the completion of these activities are
typically included in the decommissioning cost estimate because there may be a
legal obligation imposed by the state or local government, or both, for ultimate
release of the property.
Under 10 CFR Section 50.75, each nuclear power plant licensee must report to the NRC every two years
the status of its decommissioning fund for each reactor or share of a reactor that it owns. At or about
five years before the projected end of operations, each power reactor licensee must submit to the NRC
a preliminary decommissioning cost estimate that includes an up-to-date assessment of the major
factors that could affect the cost of decommissioning the reactor.
In addition, 10 CFR Section 50.82 requires a nuclear power plant licensee to submit a post-shutdown
activities report (PSDAR) to the NRC, as well as a copy to the affected state(s), before or within two years
after permanent cessation of operations. The PSDAR must contain the following:
- A description of the planned decommissioning activities.
- A schedule for the accomplishment of significant milestones.
- Documentation that environmental impacts associated with site-specific decommissioning activities have been considered in previously approved environmental impact statements.
- A site-specific decommissioning cost estimate, including the projected cost of managing irradiated fuel.
Under 10 CFR Section 50.82, a nuclear power plant licensee is also required to submit an LTP at least
two years before its license is terminated. The LTP must include the following:
- A site characterization.
- Identification of remaining dismantlement activities.
- Plans for site remediation.
- Detailed plans for the final survey of residual contamination at the site.
- A description of the end use of the site, if restricted.
- An updated site-specific estimate of remaining decommissioning costs.
- A supplement to the environmental report.
5.4.2 Nuclear Plant Decommissioning Alternatives
The nuclear decommissioning cost estimate must reflect the type of decommissioning alternative
selected. In accordance with 10 CFR Parts 30, 40, 50, 51, 70, and 72, a nuclear power plant licensee may
choose from three decommissioning alternatives: DECON, SAFSTOR, or ENTOMB. These alternatives are
summarized in the diagram below.
In general, decommissioning must be completed within 60 years of the plant’s
cessation of operations. A time beyond that would be considered only when
necessary to protect public health and safety in accordance with NRC
regulations. The duration of operations depends on the time prescribed by the
operating license. Historically, nuclear facilities have typically been
permitted to operate for a period of 60 years based on an initial license of 40
years and a license renewal for an additional 20 years. More recently, some
licensees have sought a second license renewal to extend the life of their
permitted operating period from 60 years to 80 years. Life extensions affect
when a licensed plant is shut down and eventually decommissioned. If a
licensee’s application for a life extension is approved, the licensee will need
to prepare (1) assumptions about when spent fuel will be removed from the site
(i.e., before or after plant shutdown) and (2) a revised decommissioning
timeline.
Licensees often change their decommissioning alternative selection during the
life of the plant. For example, a licensee that originally anticipated
decommissioning a power plant under the DECON alternative may change this
decision and select SAFSTOR on the basis of external factors. If the
decommissioning alternative is changed, the decommissioning cost estimate must
be revised accordingly.
5.4.3 High-Level Radioactive Waste
Highly radioactive byproducts of the reactions that occur inside nuclear reactors are called high-level
radioactive waste. There are two types of high-level radioactive waste: (1) spent fuel when it is accepted
for disposal and (2) waste materials remaining after spent fuel is reprocessed. High-level radioactive
waste must be handled and stored with care because of its highly radioactive fission products.
The only way that radioactive waste can become harmless is through decay. However, it can take
hundreds of thousands of years for high-level radioactive waste to fully decay. For that reason, high-level
radioactive waste must be stored and finally disposed of in a way that provides the public with adequate
protection for a very long time.
In 1982, Congress passed the Nuclear Waste Policy Act, assigning the federal
government’s long-standing responsibility for disposal of spent nuclear fuel
created by commercial nuclear generating plants to the U.S. Department of Energy
(DOE). The DOE was to begin accepting spent fuel by January 31, 1998; however,
no progress has been made to date in the removal of spent fuel from commercial
generating sites. In January 2013, the DOE issued the document Strategy for the Management and Disposal of Used
Nuclear Fuel and High-Level Radioactive
Waste (the “January 2013 document”). In its January
2013 document, the DOE stated that “[w]ith the appropriate authorizations from
Congress, the Administration currently plans to implement a program over the
next 10 years that [a]dvances toward the siting and licensing of a larger
interim storage facility to be available by 2025 that will have sufficient
capacity to provide flexibility in the waste management system and allows for
acceptance of enough used nuclear fuel to reduce expected government
liabilities.”
Completion of the decommissioning process is dependent on the DOE’s ability to remove spent fuel
from the site in a timely manner. As a result of the DOE’s current inability to accept the spent fuel,
commercial generating sites have been storing their high-level radioactive waste in the ISFSI, which
is typically located on the same property as the nuclear reactor. Costs associated with the long-term
storage of the spent fuel are typically included in the decommissioning estimate. Costs for storage
include operation and maintenance of the ISFSI and security as required under NRC regulations.
It is important to consider the uncertainties associated with both the requirements related to the
storage of spent nuclear fuel and the timing and ultimate disposal of spent fuel, as well as how those
uncertainties may affect ARO cost estimates. Three approaches have been observed in industry with
respect to the estimation of when the DOE will be able to accept spent fuel from a nuclear power plant:
- The DOE will not be able to accept spent fuel, and the material will remain on-site indefinitely.
- The DOE will accept the spent fuel at a later time based on an adjustment to the pickup date provided in the DOE’s July 2004 Acceptance Priority Ranking & Annual Capacity Report, taking into account the 2025 spent fuel pickup start date provided in the DOE’s January 2013 document.
- An approach similar to that in (2) above, but with a spent fuel pickup start date later than 2025 based on professional judgment.
In addition, many of the commercial generators have entered into
settlement agreements with the DOE to obtain reimbursement from the DOE for
costs related to spent fuel that were incurred as a result of the DOE’s delay in
taking possession of spent fuel. In practice, nuclear power generators have
obtained (1) reimbursements from the federal government or state regulatory
agencies for operation and maintenance costs or (2) have recovered other
monetary damages associated with the federal government’s failure to begin
removing spent nuclear fuel and other radioactive waste from former nuclear
reactor sites. Reimbursement can be sought through either settlement agreements
or damage claims. If a utility has a settlement agreement with the DOE, the
utility can seek annual reimbursement for any delay-related nuclear waste
storage costs incurred during the year. In the absence of a settlement agreement
with the DOE, a utility can file a claim for damages in the U.S. Court of
Federal Claims. Unlike settlements, which cover all past and future damages
resulting from the DOE’s nuclear waste delays, awards by the U.S. Court of
Federal Claims can cover only damages that have already been incurred;
accordingly, utilities must continue filing damage claims as they accrue
additional delay-related costs.
The NRC is currently developing new regulations that will
implement lessons learned from transitioning several plants from operating to
decommissioning since 2011. According to an August 2019 report by the NRC’s Office of the Inspector General on the
audit of the NRC’s transition process for decommissioning power reactors, the
NRC estimates that the new regulations will save licensees, the NRC, and
taxpayers approximately $19 million per decommissioning reactor. Issuance of
such regulations could potentially be a material triggering event requiring
revision of decommissioning cost estimates.
Footnotes
1
The term “Part 50 license” refers to 10 CFR Part 50, the
citation to the corresponding regulations in the Code of Federal
Regulations.