MANAGEMENT OF RADIOACTIVE WASTE
The operation and dismantling of nuclear facilities generates nuclear waste and spent fuel that must be safely managed.
As can be seen in the Guideline Iberdrola Generación Nuclear must not only comply with legislation, but also aim for best practice and continuous improvement. Currently all of Iberdrola's nuclear power plant in operation are in Spain, but in the event that should Iberdrola Generación Nuclear expand its nuclear power interests to other countries, the relevant national and international legislation, regulations and requirements will be taken into account.
In the case of Spain, currently the only case applicable for Iberdrola Generación Nuclear nuclear business relating waste management, the legal and national management framework is the following:
The Nuclear Energy Act, defined in article 2, paragraph 9, defines radioactive as:
"Any material or waste product, for which no further use is intended, that contains or is contaminated with radionuclides in concentrations or activity levels higher than those established by the Ministry of Industry and Energy and the previous Nuclear Security Council Report".
The Safety Series Nº 11-G-1.1 of the IAEA (International Atomic Energy Agency) presents the classification of nuclear waste in the following classes:
- Low activity: Waste containing low levels of radionuclides that do not require shielding during transport and handling.
- Medium Activity: Waste with a radionuclide content that requires shielding and heat dissipation equipment during transport and handling.
- High Activity
- Highly radioactive liquids primarily containing fission products, like some actinides, that are separated during reprocessing of spent fuel or chemicals (aqueous waste from the first cycle solvent extraction and accompanying waste streams).
- Any other waste with intense activity levels sufficient to produce significant amounts of heat through radioactive decay.
- Spent fuel from the reactor, if declared as waste.
In this same legislation, exempted waste is defined as waste containing such small quantities of radioactive material that it is not considered radioactive and is exempt from regulatory control. The activity concentration recommended for these materials is between 0.1 Bq/g and 10E4 Bq/g.
- Council Directive 2011/70/EURATOM of 19 July 2011, establishing a Community framework for the responsible and safe management of spent fuel and radioactive waste.
Other Guides from the IAEA, such as the Safety Standard 111-S-1, also outline the criteria to be considered for radioactive waste management according to classification.
The objective of all phases of the management of radioactive waste and spent fuel is to have effective measures to protect workers, the public and the environment from the potential risks and harmful effects of ionizing radiation, now and in the future, as stated in the Joint Convention on the Safety Fuel Management and on Radioactive Waste Management, which was signed in Vienna on September 5, 1997, and ratified by Spain and published in the Boletín Oficial del Estado on April 23, 2001.
As indicated before, in Spain ENRESA is in charge of final management of radioactive wastes as well as decommissioning of nuclear installations. From 1989, the radioactive waste management services provided by ENRESA to the operators of Nuclear and Radioactive Facilities are governed by contracts, based on the corresponding “type contracts” approved by the Ministry of Industry. This applies for the entire duration of the life of the facility, including the decommissioning of nuclear power plants.
Radioactive Waste and Spent Fuel
The General Radioactive Waste Plan (GRWP) applies to all radioactive waste produced in Spain, and therefore to all the radioactive waste produced in all nuclear power facilities of Iberdrola Generación Nuclear, and is the primary reference document for the strategies and actions to be carried out in Spain in various fields of radioactive waste management and decommissioning, along with the relevant economic and financial study. It also presents the main data related to the generation of radioactive waste, disposal programs, facility capacity, costs and revenues, etc., so that, overall, it has its own identity to be configured as a compendium of planning in this area in Spain. It is approved by the Consejo de Ministros (Council of Ministers) and is reviewed and updated periodically. Since the creation of ENRESA, there have been six revisions of the General Radioactive Waste Plan, which have marked the main priorities and objectives of integrated waste management system of Iberdrola Generación Nuclear, as owner and operator of nuclear plants that have been incorporated, developed and implemented.
The Consejo de Seguridad Nuclear (Council of Nuclear Security), the responsible body in Spain for Nuclear Safety and Radiation Protection Plans, approves Waste Management of Nuclear Power Plants and conducts periodic inspections to verify compliance. Additionally, the International Atomic Energy Agency (IAEA), as the international body responsible for fulfilling the No Proliferation Treaty, controls the inventory of spent fuel stored in pools at power plants.
The General Radioactive Waste Plan is published with the aim of improving the management of waste generated at each facility. In particular, Iberdrola Generación Nuclear maintains the inventory of waste, minimizes its generation, recycles and recovers waste to the extent that it is technically and economically feasible, and prepares the waste materials (final waste) for management. The General Radioactive Waste Plan also serves to ensure that no radioactive waste is managed by conventional means and to forecast all types of radioactive waste that can be generated, including that from dismantling.
The General Radioactive Waste Plan considers the risks, both radiological and otherwise, that are associated with radioactive waste, to define global solutions. The General Radioactive Waste Plan within Iberdrola Generación Nuclear serves as a:
- Tool for the improvement and progress for waste management.
- Tool for internal communication and, where appropriate, external management of radioactive waste.
- Commitment to proper management of radioactive waste, according to general rules for the operation of its facilities.
The General Radioactive Waste Plan establishes the management lines for all types of solid radioactive waste and spent fuel and associated temporary storage, so that:
- Radioactive waste generated as a result of the operation of Iberdrola Generación Nuclear Power Plants is managed according to the methodologies adopted by ENRESA and reflected in the specific procedures for each plant.
- Currently, Iberdrola Generación Nuclear's nuclear power plants store spent fuel assemblies in the pools of each plant and additionally, in some power plants, in dry storage containers, arranged in their respective Individual Temporary Storage (ITS) in accordance with the provisions of the current 6th General Radioactive Waste Plan.
- The systems of waste treatment in Iberdrola Generación Nuclear´s power plants are designed to process liquids and gases that are potentially radioactive and minimize their emission.
To obtain the authorization of operation, Iberdrola Generación Nuclear´s nuclear power plants must submit to authorities a Waste Management Plan for each facility, which states the criteria and methods that ensure that waste management is safe, traceable, and takes into account:
- The situation in the facility, in terms of generation, treatment and waste management.
- The identification of the origin of the waste.
- The alternative system and management processes and their improvements.
- Proof of the adequacy of management is shown and the possibility for improvements.
- The planning for implementation of identified improvements.
As indicated above, Iberdrola Generación Nuclear applies the general principle for reduction, reutilization, separation, recycling and recovery in radioactive waste management. Reduction is based on the contained use of raw materials and the restriction of materials and products entering the radiological controlled area to avoid possible radioactive contamination. Further application of this principle includes significant reductions in generation achieved through:
- Good control of technical processes where waste is generated (i.e. minimizing leaks, monitoring filters efficiency, etc.).
- Modifying and improving those processes (i.e. upgrading demineralizers efficiency, increasing compacting capacity, etc.).
- Introducing innovative new processes (i.e. in-drum drying system, reanalyzing scale factors for clearance levels, etc.).
Iberdrola Generación Nuclear applies the principle of reutilization by encouraging additional use of materials which have been found clean and without risk to personnel and pollution control (reuse of personnel working clothing prior to washing, personal tools). The principles of separation and recycling try to manage all of the waste including that which is radioactive, following the criteria for minimization at the source (for which infrastructure has been implemented to separate the waste at collection points where products are collected separately and, where necessary, adopting human resources that perform specific tasks of direct measurement of radioactive waste, to select and separate those without contamination). The promotion of reutilization, as well as separation, and recycling is done in the training sessions taught by staff in aspects of environmental and radiation protection. In regard to recovery, Iberdrola Generación Nuclear processes with authorized managers all collected sub products (paper, cardboard, scrap metal, plastic) with the aim of giving value to these materials as a solution before considering them waste.
In addition to always prioritizing the minimization of waste generation, Iberdrola Generación Nuclear works with competent bodies to obtain authorizations clearance of radioactive waste from regulatory control, such as waste oil or sludge of very low activity, melting of big and heavy slightly contaminated components, etc. In these cases, management at Iberdrola Generación Nuclear is based on reducing the generation of radioactive waste by following the corresponding conditional authorization allowing the same treatment as conventional waste.
Extensive Research and Development and Innovation is either promoted or supported by Iberdrola Generación Nuclear in this area in coordination with ENRESA, R&D bodies and national authorities.
Safety assessments of different kinds and frequencies are carried out during the whole life of the projects. Specifically during the operation phase the following amongst others can be mentioned: annual quality assurance audits, biennial company safety review board audits, decennial comprehensive periodic safety review. All of these are performed by the licensee, in addition to the frequent audits performed by the regulatory authority.
Decommissioning Radioactive Waste
As mentioned before, according to the Spanish legislation the responsibility for the management of activities arising from the decommissioning and dismantling of nuclear facilities in Spain lies with ENRESA.
The dismantling of Iberdrola Generación Nuclear nuclear power plants is financed through part of the funds that the company transfers to ENRESA throughout the operating lifetime of their facilities. The responsibility to estimates the cost of decommissioning activities covered by the GRWP corresponds to ENRESA who calculates those costs based on waste production and decommissioning plan estimations, and review this regularly for fee calculations.
As indicated in the GRWP, ENRESA performs generic studies on the dismantling of NPP's of the type installed in Spain (1,000 MWe PWR and BWR) in order to optimise future specific projects and obtain a better estimate of the costs and wastes generated. The results of these studies conclude that the total dismantling of a 1,000 MWe light water nuclear power plant gives rise to some 10,000 m3 of VLLW (Very Low Level Waste), along with some 3,000 m3 of LILW (Low & Intermediate Level Waste) and 110 m3 of higher or intermediate level waste (ILW). With these data, taking into consideration the number and type of reactors owned by Iberdrola Geneneración Nuclear, the amount of predicted decommissioning waste estimated to be generated during the dismantling of Iberdrola Generación Nuclear NPPs rises to some 34,738 m3 of VLLW, along with some 10,421 m3 of LILW and 382 m3 of higher or ILW.
These estimations for predicted or the real amounts of decommissioning wastes will be updated when new revisions of the GRWP are provided by ENRESA.