The work of resident inspectors in Spanish nuclear power plants
In depth - October 18, 2023

The work of resident inspectors in Spanish nuclear power plants

A resident inspector is a highly trained and skilled specialist employed by the Nuclear Safety Council (CSN), the Spanish nuclear regulatory body. This specialist carries out permanent supervision inside a nuclear power plant, which involves continuous on-site inspection of the plant's compliance with current legislation and the operating conditions established for the plant.

Constant supervision

Safety is an absolute priority in the operation of nuclear power plants, and in countries with nuclear facilities the nuclear regulator supports it through the constant work of specialized personnel assigned to the different plants. In Spain, this work is carried out by the Nuclear Safety Council (CSN). To guarantee effective control and supervision, the CSN deploys a specialized team in all nuclear power plants. In addition, it provides constant supervision to ensure that nuclear power plants operate in accordance with the highest safety standards and current legislation.

Resident inspectors are technical teams from the Nuclear Safety Council. They ensure constant and effective supervision and control at Spanish nuclear power plants

Mapa centrales nucleares espanolas
Situtation of the Spanish nuclear reactors

The role of resident inspectors

Resident Inspectors (RI) are a permanent inspection team. RI personnel belong to the Subdirectorate of Nuclear Facilities within the Technical Directorate of Nuclear Safety. Their main purpose is to continuously and directly supervise the plants' operations. They are responsible for evaluating compliance with security requirements, as well as informing CSN of any deviation or incident that may affect security. They are the "eyes and ears" of CSN inside nuclear power plants.

Resident inspectors cannot remain at the same site for more than ten years, in order to maintain the independence and objectivity of their work.


To become resident inspectors, candidates must have a solid academic background in nuclear engineering or other fields related to nuclear safety. They must also go through a rigorous selection process that includes theoretical and practical tests, interviews and psychological evaluations. Once selected, they receive specific training for the position; this training can last several months.

In their work they must apply a specific system: The Integrated Nuclear Power Plant Supervision System.

The work of resident inspectors in Spanish nuclear power plants
A resident inspector at work at the Vandellós II nuclear power plant (Photo: CSN)

The Integrated Nuclear Power Plant Supervision System (SISC)

The Integrated Plant Supervision System (SISC) is a fundamental tool for resident inspectors. The CSN implemented SISC in 2007 based on the US model, to improve the supervision of nuclear power plants in Spain. This system is based on a set of plant performance indicators and established inspection procedures, which facilitate continuous observation of the plant's performance and evaluation of inspection results.

The results of the indicators are classified into four levels of importance for safety:

  • Very low (green)
  • Low to moderate (gray)
  • Substantial (yellow)
  • High (red)

CSN periodically publishes the results. Here you can see the data for the first quarter of 2023.

Permits and structure

Resident inspectors are considered agents of authority and may freely access the entire nuclear site without prior notice, without interfering in its daily operation. If an obvious danger is detected, they have the authority to order the immediate suspension of operations or work, notifying the causes to CSN, the Ministry for the Ecological Transition and Demographic Challenge and the subdelegation of the Government of the province where the site is located.

Resident inspectors are considered agents of authority and have free access to the entire nuclear site

The structure of the RI team varies depending on the location of the plant:

  • In operating nuclear power plants there is one resident inspector and one or two deputy resident inspectors.
  • In nuclear power plants that are permanently shut down, there is one resident inspector.

Functions and responsibilities

Resident inspectors must fulfill several key functions:

  • Daily supervision: Their day starts early in the morning with a thorough review of the nuclear plant's reports and records. After consulting the operation log and work orders, they meet with the plant's management to share information regarding the current status of the plant and the planned activities. This includes any incidents that may have occurred since their last meeting.
  • Constant communication: Every day, resident inspectors communicate with the coordinator and support inspectors at CSN to report on the most significant incidents that have taken place at the plant. This communication ensures that the regulatory body is aware of any issues or deviations in real time.
  • Control room supervision: Resident inspectors spend part of their day in the control room, gathering information on the current status of the plant and verifying safety-critical systems. Any anomaly or irregularity is immediately detected and reported.
  • Control rounds: The RI make rounds of the plants inspecting areas with equipment that is important to safety or with significant radiological risks. They visit the "controlled area" following strict radiation protection procedures such as wearing personal protective equipment.
  • Review of the Corrective Action Program (PAC): They review the PAC, a database where improvement activities or suggestions are recorded to correct any incident, no matter how small. This ensures that even minor issues are properly addressed and corrected.
  • Weekly report: Every Friday, the RI send a report to the CSN including all incidents and observations at the plant during the week. This document is essential for the evaluation of safety and regulatory compliance.

Work at emergencies or emergency drills

In emergency situations, the experience and knowledge of resident inspectors facilitate a quick and effective response to potential incidents.

In the event of an emergency (or a drill, where the protocol is followed with the same rigor as if it were real), these inspectors take on key roles in responding to the crisis. The senior resident inspector immediately assumes the leading position of the Radiological Group and advises the director of the local Nuclear Emergency Plan on protective measures and areas of application for these measures. They also manage the information and radiological protection of the population and personnel.

In emergency situations, the experience and knowledge of resident inspectors facilitate a quick and effective response to potential incidents

Resident inspectors at nuclear power plants in decommissioning

Inspection and control at nuclear power plants in decommissioning are also the responsibility of the resident inspectors from the Nuclear Safety Council. At this stage, the inspection activities focus on surveillance and radiological control of dismantling work.

The RI continues to closely monitor decommissioning activities and provides regular reports on its progress. Aspects such as temporary modifications to systems, equipment segmentation and radioactive waste management must be considered.

The RI has several key functions:

Radiation Safety: The IR closely monitors radiation protection measures applied to workers, and checks that exposure limits are met. This includes verifying the effectiveness of containment barriers and the proper management of radioactive waste.

Waste management: The IR checks that waste is safely handled and stored in accordance with regulations. They also supervise the management of contaminated materials and components.

Disassembly supervision: They continue to conduct inspection rounds on site during dismantling, in order to verify that equipment and components are properly removed, disassembly procedures are followed and there are no radioactive leaks. They also assess the condition of structures and equipment as they are dismantled.

Regulatory compliance: The IR ensures that procedures are followed and current regulations are met. Any deviations are recorded and immediately addressed to keep the plant safe.

At nuclear power plants in decommissioning, the IR continues to perform surveillance on safety, waste management and dismantling

Guardians of security

Resident inspectors are the guardians of nuclear safety and security at Spanish plants. Their work is essential to guarantee that these facilities operate safely and comply with current legislation. From routine monitoring to emergency response and decommissioning, these professionals have a critical role in the safe and responsible management of nuclear energy throughout all stages. Nuclear safety is a constant commitment, and resident inspection is a vital component.

Source: CSN

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