Reduction and Resource Recycling of
High-level Radioactive Waste
through Nuclear Transmutation

PROGRAM OUTLINE

Project 4
[Transmutation System and
Elemental Technology]

Elemental Technology Development of Particle Accelerators System Applied for Transmutation

Project leader
Hiroyoshi Sakurai

Affiliation: RIKEN Nishina Center for Accelerator-Based Science
Group Director
Research Fields: Experimental Nuclear Physics

Transmutation System and Elemental Technology

Purpose: Elemental technology development of a particle accelerator system applied for transmutation

Acceleration by high-frequency electric field (Lorentz force)
(Lorentz force = electric charge × high-frequency electric field)
  • What is the high-frequency electric field inside the cavity?
An electric field where the sign is reversed at constant intervals
  • What is a superconducting cavity?
A cavity refers to a space that confines a radio frequency electromagnetic field surrounded by metal. By using a pure niobium material and cooling to the temperature of liquid helium, the loss due to high-frequency currents can be reduced to the largest possible degree, and a strong accelerating electric field can be generated.
  • QWR-type cavity linear accelerator
By arranging a plurality of cavities, particles are accelerated to a high speed. When this takes place, it is important to change the gap interval and cavity resonance frequency according to the particle velocity.

Current Results

New Nuclear Reaction Control Technology (Theme Selected by PJ2 public offering in FY2015)
Toward implementation of a demonstration test of energy recovery type (ERIT) accelerator

[ERIT principle and transmutation by neutrons]

Energy recovery internal target:ERIT(Energy Recovery Internal Target)

Principle Demonstration Aim

Principle Demonstration Challenges

・Achieving both beam acceleration and storage
Fixed RF Frequency: Meandering acceleration
Fixed Field: zero chromatic aberration

・Large Acceptance (3D): ionizing beam cooling


(Characteristics of ERIT)

・Energy recovery
Particle generation at highest energy

・Thin target: Avoid particle generation loss

・Avoid increase in emittance
Ionization Beam cooling

・Beam turning: effective length target
Effective target length Leff = Lt x N