National Inventory

In Spain, the definition of radioactive waste is established in article 2 of Law 25/1964, from 29th April, about nuclear energy (LEN) as follows: “Radioactive waste is any material or waste product, for which there is no expected use, that contains or is contaminated with radionuclides in concentrations or levels of activity over those established by the Ministry of Ecological Transition and Demographical Challenge, with a previous report of the Nuclear Safety Council (CSN)”.

According to article 6.c) of Royal Decree 102/2014, among the contents of the GRWP there must be “An inventory of all spent nuclear fuel and radioactive waste, as well as estimates of future amounts, including from decommissioning. This inventory shall clearly indicate the siting and amount of spent nuclear fuel and radioactive waste, according to a classification that takes into account the final management scheduled for it”. Thus, the final management route is key in the classification of radioactive waste. Although there are many types of radioactive wastes, these wastes are categorized in Spain according to the management facilities authorized for a volume, radiological inventory and specific activity concentration limits, depending on the nature of the different radionuclides present. These categories are:

Radioactive waste classification

Low and Intermediate Level Waste, short-life (LILW)

Those whose activity is mainly due to the presence of radionuclides beta-gamma emitters, with a short-medium disintegration period (below 30 years) and whose content in long-life radionuclides is very low and limited. This group includes low- and intermediate-level radioactive waste (L&ILW), which are a subset of low-level radioactive waste (LLW) and, in general, have specific activities between 1 and 100 becquerels per gram, reaching up to several thousand in the case of some low-radiotoxic radionuclides or when dealing with small quantities.

Special Waste (SW)

This group includes nuclear fuel cladding, neutron sources, used intranuclear instrumentation, or replaced components from the reactor vessel system and reactor internal components, generally of a metallic nature, which, due to their radiological characteristics, are not suitable for management at the C.A. El Cabril facilities. As a long-lived and significantly active radioactive waste, its temporary and final management is planned in a similar way to that of the HLW.

High Level Waste (HLW)

Those that contain significant concentrations of long-lived alpha emitters with half-lives greater than 30 years, in significant concentrations, that generate heat due to radioactive decay, since their specific activity is high. Its main exponent is the spent nuclear fuel (SNF) discharged from nuclear reactors.

Did you know?

Radioactive isotopes tend to become stable elements, that is, they lose their radioactivity. The time a radioactive substance takes to reduce its activity to the half is called "semidesintegration period".

Origin of the radioactive wastes in Spain

The following map shows the main radioactive waste producers in Spain.

Nuclear Power Plants in operation

Main producers of radioactive wastes. Currently, there are 7 reactors in operation, in 5 sites: Almaraz I and II (Cáceres), Cofrentes (Valencia), Vandellós II and Ascó I and II (Tarragona), Trillo (Guadalajara).

Nuclear Power Plants being dismantled

Santa María de Garoña Nuclear Power Plant (Burgos) which is currently in the dismantling phase 1.
José Cabrera Nuclear Power Plant (Guadalajara), which is currently in the final phase of decommissioning.
Vandellós I Nuclear Power Plant (Tarragona), currently in the latency phase after its partial dismantling.

El Cabril Disposal Facility

El Cabril is the Spanish disposal facility for very low, low and intermediate lever radioactive waste. It is located within the minucipal area of Hornachuelos (Córdoba).

Nuclear fuel manufacturing facility “Juzbado” (Salamanca)

Nuclear fuel manufacturing facility “Juzbado” (Salamanca), where oxide uranium fuel elements for NPP reactors are manufactured.

Decommissioned research reactors

Reactor JEN-1 (Ciemat, Madrid), Argos (Barcelona) and Arbi (Bilbao). These research reactors are currently dismantled, and their associated wastes have been sent to C.A. El Cabril.

Research centre

Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (Ciemat), in Madrid, has a series of radioactive facilities in operation and a series of nuclear facilities already dismantled.

(UC, Uc) Uranium mills

Uranium mills, already closured and located in Andújar (Jaén), La Haba (Badajoz) and Saelices el Chico (Salamanca).

Radioactive facilities

We consider those facilities located all over the national territory that have technical-administrative specifications signed with Enresa at inventory date. According to Royal Decree 1836/1999, of 3^rd December, radioactive facilities are defined as:

Any kind of facilities that have an ionizing radiation source.
Devices that produce ionizing radiation working with a potential difference over 5 kilovolts.
Locations, laboratories, factories and facilities that produce, use, own, treat, manipulate or store radioactive materials, except disposal facilities.

National Inventory

According to article 38 bis of the Law 25/1964, from 29th April, on Nuclear Energy (LEN), radioactive waste management in Spain, including spent fuel, and decommissioning, dismantling and closure of nuclear sites, is categorized as an essential public service entrusted to the State, being this responsibility submitted to Empresa Nacional de Residuos Radiactivos, S.A. S.M.E. (Enresa), according to the General Radioactive Waste Plan (GRWP) approved by the Government. Currently, the 7th General Plan for Radioactive Waste, approved by the Government on 27th December 2023.

Additionally, Royal Decree 102/2014, from 21st February, for a safe and responsible management of the nuclear spent fuel and the radioactive wastes, sets in its article 9, as one of Enresa’s responsibilities, the preparation and management of the National Inventory for Spent Fuel and Radioactive Wastes, which shall include wastes and spent fuel definitively disposed of, after the closure of the installation where they are allocated.

This is the reason why, in 2014, Enresa began working in a new National Inventory for Spent Fuel and Radioactive Waste, closed as at 31st December 2015. Since its creation in 1984, Enresa has developed an inventory of radioactive wastes in Spain, with the data received from all waste producers. Since then, there has been a close cooperation and an improvement on the detailed knowledge of the situation, which has allowed the elaboration of more precise strategies and management programmes.

The National Inventory is based on a series of reports, which reflect both the origin of the radioactive wastes and spent fuel, and the hypothesis considered to reach the final values for the expected wastes, according to the established uncertainties.

In the interest of transparency, Enresa acknowledges the importance of having the national inventory data publicly available in a simple and accessible way for the population.

Inventory of 31st December 2022

Within the inventory data, it is interesting to know the origin of the data and the way the information is generated.

Origin of the data for wastes generated at one date

The data for elaborating the Inventory come, mainly, from the producers of spent nuclear fuel and radioactive wastes. Enresa receives the information according to the technical-administrative specifications for accepting nuclear spent fuel and radioactive wastes, as required in article 11 of Royal Decree 102/2014.

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Annually, nuclear power plants in operation prepare a preliminary program of waste generation during operation that includes:

Number of waste packages for each waste stream to be produced in the next 5 years of operation, and those produced during the previous year.
Estimates of fuel elements to be discharged in the next 10 years of operation, and the spent fuel elements generated during the previous year.

All this information sent by the waste producers is included in the Data Bases developed by Enresa to control the inventory of wastes.

In the case of wastes coming from the dismantling of nuclear power plants and other facilities, Enresa, as the company responsible of these projects (up to now in Vandellós I, Pimic/Ciemat, José Cabrera and Santa María de Garoña), has developed specific management systems in order to control the materials and wastes generated and their subsequent management. In case they are finally managed as radioactive waste, this information is turned over in the Data Bases already mentioned.

In terms of future estimates for the dismantling of Spanish nuclear facilities, Enresa has developed some studies to be able to make some forecasts on quantities, typologies and uncertainties.

For radioactive facilities, the technical-administrative specifications include the obligation of the owner to inform Enresa about the estimates of radioactive waste generation and the possible changes that may occur. For other facilities, future previsions are done from the basis of the previous experience.

The inventory of wastes generated as of 31st December 2022, is reflected in the following table:

Table that reflects the inventory of wastes generated as of 31st December 2022, during the operation and the dismantling of the NPPs (67415 m³ and 15051 m³).
Origin of the waste	VLLW (m³)	LILW (m³)	SW (m³)	HLW and SF (m³)	TOTAL (m³)
Waste from operation	11.700	37.100	15	8.900	57.715
Waste from dismantling	19.600	4.000	185	---	23.785
TOTAL	31.300	41.100	200	8.900	81.500

The volume given is considering the waste after disposal.

From the total amount of LILW and VLLW generated, some of them are already disposed in the vaults of C.A. El Cabril, others are temporary stored in that facility, and some others are still in the producers’ facilities. The graphics below show the distribution of this type of wastes according to their location:

VLL Wastes generated

LIL Wastes generated

Additionally, this is the amount, at inventory date, of VLLW and LILW disposed in vaults or structures of C.A. El Cabril facility, counted on primary waste packages received on site:

Table that shows VLLW and LILW disposed in vaults or structures of C.A. El Cabril facility, counted on primary waste packages, being VLLW 21453 m³ and LILW 35525 m³.
VLL Wastes (m³)	LIL Wastes (m³)
23.375	35.832

Regarding the fuel elements generated, although for the national inventory the occupational volume is estimated in m3, it is interesting to know the number of total fuel elements generated, and the corresponding uranium tones:

Table indicating the total amount of fuel elements generated, 15.838, and the corresponding uranium tones: 5.246.
Fuel elements generated	Uranium tones
17.286	5.799

Spent Fuel Characteristics

Nuclear fuel consists of a series of cylindrical ceramic pellets of uranium oxide, whose U-238 is enriched to a variable degree (up to 5%) with U-235. These are encased in zirconium alloy tubes to create fuel rods, which are arranged into a structure to form the fuel assembly.

Since it is in the reactor, the uranium and other radionuclides generated are subject to neutron capture and nuclear fission reactions, resulting in fission products, activation products and the generation of plutonium and minor actinides. The composition of these products includes virtually every element of the periodic table.

Quantities and characteristics of the components of the irradiated fuel depend on its initial U-235 enrichment, its degree of burnup and the operation of the reactor.

Fuel assembly model

Expected generation

In order to estimate the future generation, a series of hypothesis and the reference scenario considered in the General Radioactive Waste Plan must be taken into account.

Reference Scenario

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Open Fuel Cycle; that is, the reprocessing option for spent fuel is not considered.
Lifetime of NPPs in operation, with a working rhythm similar to the current one, according to the following reference scenario for the cessation of operation:

Table with the lifetime of NPPs in operation, where reactors are identified, and the dates of beginning and ceasing operation are shown.
Reactor	Date of beginning operation	Date of ceasing operation
Almaraz I	01/09/1983	11/2027
Almaraz II	01/07/1984	10/2028
Ascó I	10/12/1984	10/2030
Ascó II	31/03/1986	09/2032
Vandellós II	08/03/1988	02/2035
Trillo	06/08/1988	05/2035
Cofrentes	11/03/1985	11/2030

To make the calculation for dismantling wastes, we consider 10 years for the dismantling of each NPP, except for Vandellós I where 15 years are considered from 2030.
Total dismantling of the NPPs that are currently in operation, to begin 3 years after their definitive shutdown.
The period between the definitive shutdown and the beginning of the dismantling is included in the operational phase for the purposes of waste generation.
In the case of radioactive facilities, the estimate for waste generation is elaborated according to the waste treatment done in C.A. El Cabril.
The prevision of wastes to be managed coming from expected facilities for spent fuel, HLW and SW management, as Decentralized Temporary Storage (DTS) and the Deep Geological Repository (DGR) is also considered.

Hypothesis

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Hypothesis to calculate estimates in operational phase

Estimates proposed for the annual generation are done according to the NPPs yearly previsions of generation for the next five years.
The estimate for VLLW and LILW is calculated considering the volume of the waste, once conditioned for its final management in C.A. El Cabril.
In the case of final disposal for spent fuel, we have considered for its quantification DGR capsules.
For special wastes, their final disposal is in capsules similar to the ones used in José Cabrera NPP dismantling (GWC).
For all streams and types of waste, a range of uncertainties are considered: 15% for VLLW/LILW, 50% for SW, between 10 and 30 elements for spent fuel.

Hypothesis to calculate estimations in dismantling phase

For NPPs PWR type (Ascó I and II, Almaraz I and II, Vandellós II, Trillo), very similar in their designs, the amount of wastes to be generated is defined in a detailed study developed for Vandellós II NPP.
According to the operational experience of José Cabrera’s dismantling, for other NPP’s dismantling projects we make an estimate of the secondary wastes generation (compactable material, ventilation filters, etc.), of the volume of special waste expected to be managed, of the rejected material from the releasing process (radioactive material that, after its measure, does not comply with the criteria defined and approved by the CSN for releasing), and also of the conditioning of the wastes according to the type and container.
In the case of concrete, we consider the scarification treatment that will be applied to contaminated surfaces, depending on its radiological classification.
For contaminated soils we use as a reference the estimate done for José Cabrera NPP, considering between 30-60% as VLLW and the rest as releasing material.
For each NPP we get a maximum and a minimum inventory, depending on the uncertainties, which depends on the type of NPP, on the percentage of decontaminated soils, on the amount of secondary wastes generated and on the filling percentage of the final containers corresponding to each type of waste.

Total inventory at 31st December 2022

Considering all the uncertainties and hypothesis previously explained, estimates of the inventory for each type of waste, are shown below:

Table that shows the inventory at 31/12/21 by type of waste (VLW, LILW, SW, SF and HLW), the expected generation at that date, and the total inventory giving a maximum and a minimum value, in m³.
Type of waste	Estimated volume (m³)
Type of waste	Inventory at 31/12/22	Expected generation	Total inventory
VLLW	31.300	93.700	125.000
LILW	41.100	53.100	94.200
SW	200	200	200
SF and HLW	8.900	2.500	11.400
TOTAL	81.500	153.000	234.500

This implies that, at inventory date, 35% of the radioactive wastes expected are already generated. According to the estimates of the total inventory, considering the average value, the distribution related to the type of waste is as follows:

Inventario total

Table that reflects the distribution of the total inventory accoridng to the origin of the wastes.
Inventory	VLLW	LILW	SF/HLW	SW	TOTAL
Operation of NPPs	11.600	40.300	11.400	200	63.500
Dismantling of NPPs	91.000	46.500		700	138.200
Juzbado	1.000	100			1.100
Ciemat, DTS/DGR, El Cabril/others	21.400	7.300		3.000	31.700
TOTAL	125.000	94.200	11.400	3.900	234.500