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Creation of Subcritical Assembly Driven by Proton Accelerator (SAD)

#2267


Construction of the Subcritical Assembly with Combined Neutron Spectra Driven by Proton Accelerator at Proton’s Energy 660 MeV for Experiments on Long Lived Fission Products and Minor Actinides transmutation (Phase I: Design, Design Documentation and Safe

Tech Area / Field

  • FIR-EXP/Experiments/Fission Reactors
  • ENV-RWT/Radioactive Waste Treatment/Environment

Status
8 Project completed

Registration date
25.07.2001

Completion date
27.09.2007

Senior Project Manager
Tocheny L V

Leading Institute
Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna

Supporting institutes

  • State Special Project Institute, Russia, Moscow\nAll-Russian Scientific Research Institute of Non-Organic Materials named after A. Bochvar, Russia, Moscow\nNPO Mayak, Russia, Chelyabinsk reg., Oziorsk\nFederal State Unitary Enterprise Research and Development Institute of Power Engineering named after N.A.Dollezhal, Russia, Moscow

Collaborators

  • EURATOM-Ciemat, Spain, Madrid\nCEA Commissariat a l'Energia Atomique, Cadarache, France, Saint-Paul-lez-Durance\nRoyal Institute of Technology / Nuclear and Reactor Physics, Sweden, Stockholm\nForschungszentrum Karlsruhe Technik und Umwelt, Germany, Karlsruhe

Project summary

The purpose of the project is to develop and create an experimental installation (SAD) on the basis of an accelerator of protons with 660MeV of energy and a subcritical MOX blanket with uranium-plutonium fuel.

Various concepts of accelerator driven systems (ADS) for long-life plutonium isotope, minor actinide (MA) americium, neptunium, curium and long-life fission product (LLFP) incineration are now under review. These are fast reactors and subcritical systems driven by proton accelerators. For a neutron source in such systems a nucleon-hadron cascade is used, which arises at interaction of a proton beam with 0.5–2GeV of energy with the target. “Heavy” materials Pb, Pb-Bi and W are proposed for use as targets in such installations. In the operation of such an installation the activity of MA will be decreased and fuel toxicity will be determined by LLFP.

The present conceptual design of the experimental subcritical assembly in Dubna (SAD) is based on a core with nominal thermal power of 15-20kW. This corresponds to a multiplication coefficient of keff= 0.95 and to accelerator beam power of 0.5kW.

The offered project is based on computer modeling of the characteristics of the subcritical assembly executed by JINR and NIKIET experts with the use of the codes CASCADE (based on a model of intranuclear cascade evaporation, developed at JINR) and MCNP.

The given project assumes creation of a subcritical assembly on the basis of experimental fuel elements (FE) used in BN-600 reactor with MOX fuel.


The experimental electronuclear installation will include:
- 660MeV proton accelerator;
- Beam transport channel;
- Heavy replaceable target (Pb, W, Pb-Bi);
- Subcritical blanket with BN-600 type FE with Keff = 0.95;
- Protective and supervision systems;
- Control and measuring complex.

The proton beam interacts with the target and produces evaporation spectrum neutrons, which enter the blanket. The blanket containing MOX fuel surrounds the target. The lead reflector surrounds the blanket. A small beryllium insert equipped with experimental channels will be placed behind the lead reflector.

The installation will be placed in the accelerator hall, surrounded by a concrete wall no less than 2 meters thick. The hall for the installation will be equipped with a special ventilating system with control of radioactive aerosols. A beam transport line will be created for transportation of the extracted proton beam to the blanket.

A blanket based on BN-600 type FE of Russian manufacture will be used as the subcritical assembly. FE contain 27%PuO2 + 73%UO2, average density of fuel = 10.2g/cm3. The content of 239Pu in PuO2 is not less than 95%. Uranium oxide is of a depleted kind (0.4% 235U). The subcritical assembly is placed inside the concrete container that provides radiation safety at all operational modes of the installation. Thermal power of installation equals 15-20kW.


The basic tasks of the project are:
1. Design and construction of an experimental prototype of the subcritical assembly driven by proton accelerator SAD for subsequent realization of a wide research program.
2. Study of the characteristics of heavy neutron-producing targets (neutron yield, spectral and angular distributions, composition and properties of the products of the interaction of primary protons and nuclear cascade particles with the target).
3. Creation and testing of a technique for measurements and monitoring of reactivity, neutron noise of the subcritical assembly, based on the kinetic properties of the assembly, and substantiation of safety.
4. Adjustment and testing of relevant computer codes and databases, used for calculations of the ADS characteristics.
After realization of the project on the basis of the SAD installation it is planned to implement the following research program:
1. Study of the operating modes of the subcritical assembly in combination with the proton accelerator, development of techniques for measurement and control of the parameters of the facility;
2. Study of the problems of target and subcritical assembly integration, including influence of the target size and position on main SAD characteristics;
3. Measurement of the absolute value of the power gain of the installation (systems with a low level of power are most appropriate for solving this task);
4. Measurement of shielding efficiency (especially in the direction of the primary proton beam);
5. Analysis of the neutron-producing targets after long irradiation by protons, analysis of special samples (MA, LLFP), irradiated in ADS experimental channels (including the radiochemical analysis);
6. Measurements of transmutation rates for MA and LLFP in different neutron spectra.

The measurement of the neutronic characteristics of targets–converters and the subcritical assembly will be performed by a measuring system including detectors of various types of fast and thermal neutrons, activation foils placed in experimental channels inside the assembly, lead shielding and beryllium insert.

The main advantage of the given project consists in its possible fast realization, owing to the availability of the proton accelerator. Another advantage could be the existence at JINR of the IBR-30 subcritical core, driven by a LUE-40 40MeV electron linac, which will be used for tests and calibration of experimental techniques on Keff, heat release and measurement of neutronic characteristics. A further advantage is the use of standard FE for the subcritical assembly, which are serially produced in Russia (BN-600 FE), and participation in the project of institutes - developers and manufacturers of FE, subcritical assemblies and reactors.

The project is devoted to creation of the proton accelerator driven subcritical assembly based of experimental FE with MOX uranium – plutonium fuel. The project consists of two parts: design and technological ones.


At the design part, designed and budget documentation on creation of installation will be developed according to the requirements of Russian Federation, the package of documents for obtaining the licenses on allocation and creation of nuclear installation will be prepared.

At the technological part of the project the production of FE will be prepared and the preproduction batch of MOX fuel pellets will be released. The first task is the development of the concept of installation, specifications on different units and systems of installation, demarcation of zones of the responsibility of organizations participating in the project. At development of the concept of installation the results of simulation of its parameters (task 2) will be taken into account. After implementation of the first and second tasks the specifications to parts and systems of the SAD installation will be defined which will be directed in organizations participants for execution.

After that the project implementation will be carried out separately in organizations participants under JINR supervision. At the first stage the tasks on designing of the systems and parts of SAD installation and obtaining of the necessary licenses will be implemented. Within the second task the production of MOX fuel pellets will be prepared and the preproduction batch will be released.


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