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Nuclear Power Station - Decommissioning Cost Estimation

Activities involved in the decommissioning of nuclear facilities:

How is the Cost estimation approach

The decommissioning of a nuclear power plant refers to the process of dismantling and decommissioning a nuclear power plant once it has reached the end of its useful life. This process involves a number of important activities to ensure safety and environmental protection. The following are some of the main activities involved in the decommissioning of nuclear facilities:

Before decommissioning begins, detailed planning is carried out, including risk assessment and the development of a decommissioning plan. This involves identifying the radioactive components and materials present in the facility and assessing the associated risks.


The first step in decommissioning is the removal of the nuclear fuel used in the reactor. This involves safely transferring the fuel to an appropriate storage site, such as a spent fuel repository.

Before the facility is decommissioned, a decontamination process is performed to reduce the level of radioactivity in components and structures. This involves the cleaning and removal of radioactive materials present in the facility.


Once the facility has been decontaminated, the components and structures are physically dismantled. This involves the demolition and removal of contaminated equipment and structures. Special techniques and equipment are used to ensure safety and minimize the release of radioactivity.

Radioactive waste is generated during the decommissioning process and must be managed safely. This includes classification, packaging and proper storage in accordance with applicable regulations and standards.


Throughout the decommissioning process, continuous monitoring is carried out to ensure that safety and radiation protection standards are met. This includes measuring radioactivity levels and assessing environmental impacts.

Decommissioning options for nuclear plants

International Atomic Energy Agency (IAEA)

It is important to note that the decommissioning of nuclear power plants is a complex process and requires the involvement of nuclear safety and radiation protection experts. In addition, each facility may have specific requirements and applicable regulations.

When it comes to decommissioning nuclear plants, there are several options available. The choice of decommissioning method depends on various factors, including regulatory requirements, the plant’s design, the level of radioactivity, and the intended future use of the site. Here are the primary decommissioning options:

  • Immediate Dismantling (DECON):

This approach involves initiating the decommissioning process promptly after the plant permanently shuts down. The nuclear facility is decontaminated and dismantled in a phased manner. Radioactive waste is managed and disposed of as the dismantling progresses. This method allows for quicker site restoration and potential reuse.

  • Safe Enclosure (SAFSTOR):

With this option, the plant is placed in a state of long-term storage and monitored for an extended period. The facility is maintained and kept in a condition that ensures safety until the radioactivity decreases naturally over time. This approach provides additional time for radioactive decay and reduces the overall radiation exposure during decommissioning. Dismantling activities typically occur years or even decades later.

  • Entombment

Entombment involves placing the entire facility, or portions of it, in a structurally stable enclosure. This method is less commonly used and is considered a final and irreversible option. The entombed facility is monitored and maintained to ensure long-term safety.

ABEX Estimate step based time-line

The decommissioning estimate process involves several key steps in a timeline. Here’s a summarized outline:

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Step 1

Scope of work analysis

To gather data on project scope, resource requirements. Definition of objectives, and analyse regulatory requirements for decommissioning. Stablish a project team and assign responsibilities. Clearly articulate the project scope, including objectives, deliverables, and constraints.
Identification of all elements and phases of the project that will contribute to the cost. Identification and involving relevant stakeholders in the cost estimation process. Understand the specific requirements and expectations of stakeholders regarding cost information.

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Step 2

APEX Estimation Plan

Develop a detailed cost estimation plan in line with AACE International principles. Creating a baseline cost estimate for the decommissioning project. Considering factors such as labor, equipment, materials, and disposal costs. Defining the basis of estimation, such as activities, quantities, labor rates, material costs, and productivity factors. Establishing the level of detail required for accurate estimations. Choosing the  appropriate cost estimation methodologies based on the project characteristics. Creatinng a detailed Work Breakdown Structure that breaks down the project into manageable components.
Assigning cost centers and codes to each WBS element.

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Step 3

Quantities' Survey Review

The close alignment of Quantities’ Survey Review with engineering team deliverables is essential for accuracy, consistency, communication, risk mitigation, and effective decision-making throughout the project lifecycle. It ensures that the survey data accurately reflects the evolving nature of the engineering design and project scope. The Work Breakdown Structure (WBS) is a fundamental component of project management. Quantities’ survey data should align with the WBS, providing detailed information for each work package defined by the engineering team.

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Step 4

ABEX Development - BOE Report

Using Kpex historical data from similar past projects to serve as a basis for estimating costs. Analyze historical performance, costs, and productivity metrics. Choosing appropriate cost estimation methodologies approved in the Cost Estimating Plan and based on the project characteristics.
Common methodologies will depend on the maturity of data coming from the quantity survey.

We have experience in preparing decommissioning estimates (ABEX/DECOMEX) for both onshore and offshore installations around the world.

We prepare decommissioning estimates  using our proprietary estimating model based on cost benchmarking data analysis, originally developed from actual project data and regularly updated and optimized sing a know-how method to reflect current market conditions and the latest decommissioning practices.

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