Effective Decommissioning Of Nuclear Power Plant Asset

Introduction

Successful decommissioning of an Asset generally consists of four preparatory stages:

• Define the end-state of the asset
• Create a Decommissioning Plan
• Develop Scope of work
• Identify resources

The process involved in decommissioning the asset

Restoration Planning:

• Project creation/design: Estimating the cost, preparing skilled work, creating a schedule, planning storage for spent fuel, all removed waste, and preparing safety systems
• Project development: Detailed planning, Developing technology solutions, Identification of key stakeholders, and Development of support infrastructure.
• Monitoring Plan: Oversight of the plan, identifying the challenges during the operation.

Execution

• Stage 1: The process of dismantling any systems that are not related to the decommissioning process and installation of logistics in the hot zone (radioactive/hazardous zone).
• Stage 2: Dismantling the higher contaminated system parts that are larger in size as they are easier to dismantle.
• Stage 3: Dismantling the parts in the hot zone
• Stage 4: The deconstruction of radioactively contaminated system parts, removal of the operating systems, and decontamination of the buildings.
• Stage 5: Demolish the buildings for further nuclear or non-nuclear use in the future.

Strategy

• Immediate dismantling: The decontamination and dismantling process starts immediately after the termination of the operation. All contained parts must be removed or decontaminated according to the level where no more regulatory control is needed. If there are no routes for the spent nuclear fuel, it will be kept in interim storage on-site and will be decommissioned a few decades after the demolition of the power plant has been completed.
• Deferred dismantling (safe enclosure/safe storage): Remove all spent fuel from the facility. While the power plant will be kept intact in a safe and stable state to let the activity of the radionuclide naturally decay until it reaches levels that allow easier handling. Typically, after 10 years of the permanent shutdown of the nuclear power plant, the decontamination and dismantling will start.
• Safe Enclosure: Encase radioactive structures, systems, and components in a long-term storage facility. The plant will be maintained and monitored until any radioactivity is below a level that permits the termination of the plant’s license and ends any regulatory control. The majority of nuclear power plants will have radionuclide concentrations that exceeds the limits for unrestricted use even after a century. Therefore, this strategy needs special provisions for the extended monitoring period.

?Rules and Regulations

A program by International Atomic Energy Agency, IAEA included decontamination and decommissioning activities. The IAEA sees its duty here as aiding its member states in the safe, timely, and cost-effective dismantling of their nuclear sites.

Regulatory requirements:

The creation of a safe, effective, and cost-effective strategy for decommissioning each member state’s nuclear facilities must take place within the context of the country’s nuclear policy as well as its safety and regulatory requirements. Should also consider the number and types of licenses, whether the licenses are private or state-owned, the availability of waste storage or disposal capacity, future use of the site, the availability of the necessary technology and skilled workers, and the financial resources needed to complete the task.

Regulatory guidelines:

The regulatory procedure for the guidelines and evaluation of decommissioning solutions varies per Member state. Some examples are:

·????????Decommissioning regulations provide standards for decommissioning options, timing, and so forth.

·????????The need to assess the various decommissioning alternatives available for the given facility, this selection procedure may also include cost-benefit or multi-attribute assessments.

·????????The demand for a justification of the chosen option and a willingness to examine any options that the applicant can demonstrate to be both adequately safe for the environment desirable.

Regulatory standards for optimization:

An agreement must be struck between quantifiable criteria (e.g., peak risk to the individual and discount cost) and nonquantifiable factors (such as the desire to return to greenfield). The selection of a preferred decommissioning plan is generally based on an optimization analysis that involves, among other things, radiation protection. The effect of the various parameters is to be evaluated based on elements of safety and the environment, technological aspects, cost, and considerations for social and political factors.

?Budgeting and financial reporting

Every nuclear plant must be decommissioned at the end of its useful life, usually after operating for 40-60 years. The decommissioning of a nuclear plant costs around $500 million per unit, but the actual cost depends on the plant’s size and design. The cost of decommissioning can be significantly higher if the plant has become more contaminated. In some cases, the decommissioning of a nuclear plant can reach up to $1 billion per unit. A typical financial statement will take into consideration the overall dismantlement and restoration costs, regulatory and competition law proceedings, termination benefits, and the whole future storage cost.

Some factors that influence the costs of decommissioning:

• Decommissioning policy and strategy,
• Roles and duties of the diverse interested parties, and the regulatory framework
• Early planning and preparation phases prior to decommissioning, and site characterization
• Ongoing management of spent fuel and operational waste management
• Facilities for waste (final) disposal of all materials including spent fuel
• Final stage of decommissioning, de-licensing, site restoration, and reuse
• Manpower management
• Risks management, uncertainties, and contingencies.

?Risk Management during asset disposal

Two general processes to manage risk during asset disposal are categorized firstly, on a strategic level involving strategic risk management or the application of risk management to strategic challenges and strategic planning, this process is becoming popular among a variety of enterprises. An important input is the observation that the major assumptions used in decommissioning planning can be reasonably equated to the strategic assumptions used in strategic risk management. Secondly, an operational level where risks are managed during the implementation and execution of a decommissioning project. Steps in this process include establishing the context, determining risk criteria, risk assessment, risk treatment, monitoring and reviewing, communication and consultation. The former deals with the management of key assumptions, facts, strategic decisions, and related uncertainties. It is of a qualitative nature and covers aspects of the evolution of assumptions toward strategic decisions. While the latter deals with the management of risks associated with project details of the decommissioning work to be performed. It is more of a quantitative nature and covers aspects of risk escalation.

?Final Thoughts

The decommissioning programs stretch over such long timescales that the whole asset life-cycle is encompassed, including the concept, design & build operations, and finally the decommissioning. The decommissioning equipment will itself need to be decommissioned and the facilities that store the produce from the decommissioning process will also require asset management strategies to ensure the facilities operate safely in the future. There is a huge amount of asset machinery and infrastructure involved in the whole process of nuclear decommissioning and these require an asset management strategy and a whole-life asset management plan. This is what we provide at Optimal.

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