DEVELOPMENT PROPOSAL OF AN ACCELERATOR NUCLEAR INCINERATION
Shin'ichi TOYAMA, Kenji KONASHI, Nobuyuki SASAO, *Hisashi WATANABE,$TakaoURANO, $satoshi OHSAWA, $Atsushi ENOMOTO, $Hitoshi KOBAYASHI,$shozo ANAMI, $Kazuo NAKAHARA, $Y.-L. WANG and$ Isamu SATO
Power Reactor and Nuclear Fuel Corporation (PNC), Tokai Works
Muramatsu, Tokai- mura, Naka- gun, Ibaragi- ken, 319-11, Japan
Zuihou Sangyo Co. Ltd
Muramatsu, Tokai- mura, Naka- gun, Ibaragi- ken, 319-11, Japan$National Laboratory for High Energy Physics (KEK)
Oho, Tsukuba- shi, Ibaragi- ken, 305, Japan
Abstract

under the collaboration with National Laboratory for High Energy

Development proposal using an accelerator for nuclear incineration isdescribed For this purpose, a test linac which accelerates electrons up

Physics (KEK).
In Fig. 1, there is presented the state of electron power ofaccelerators all of the world, where also the position of our test linac

to 10 MeV with duty factor 20% is planning for the study of highintense beam acceleration. The major items of this year are research ofwhich will be made addressed. The basic specification of ouraccelerator is shown in Tab. 1. The results from this development will

CW(Continuous Wave) accelerating tube the development of highbe fruitful for the study of the advanced accelerator design. Data fromthe test linac will be also valuable for new type of light source,

power CW klystron and the analysis of thermal stress induced by highpositron generator and etc.
At present, it is supposed that the conceptual structure of the test
linac is like one shown in Fig. 2, where two klystrons and eight

power RF.
Introduction
There are long-lived radioactive nuclides in the spent fuels fromnuclear reactors. Recently the incineration disposal has developed inaccelerating tubes are seen. The length of the test linac is 16m. We
are planing that this accelerator facility will be constructed in the siteof PNC Tokai works.

order to transmute these nuclides into short-lived or stable ones bymeans of a reactor or a accelerator. F.P. products, especially 90sr

Subjects of the development

and 137cs which occupy the most part of nuclear waste from spent
fuels are not suited for incineration disposal only by reactor becauseof their smallness of cross section for slow neutrons. There are somemethods to incinerate those radioactivities by using accelerator, wherethe use of photo nuclear reaction high energetic proton spallation,neutron knock-out reaction and so on are candidates. We Power
Reactor and Nuclear Fuel Development Corporation (PNC) are now
developing the technique around the incineration disposal using
method with an accelerator for F. P. product.

In the case of the test linac, there are many subjects for thedevelopment, _namely beam break up (BBU) problem, CW
accelerating tube structure, thermal stress of cavity structure, highpower CW klystron with high efficiency, electron gun with goodemittance, vacuum technology, control system of linac and so on. In
this paper, we mention about the design of CW accelerating tube andhigh power klystron which are planned to research and develop thisfiscal year.
1 CW accelerating tube

Development proposal of an CW accelerator

Good energy transformation of RF to beam is of vital
importance for our lest linac. For this purpose, RF power supply
system by not only standing wave but also traveling wave with

It is important for the characteristics of an accelerator for incineration
disposal to get stable high intensity beam and good efficiency againstenergy economics. In this disposal, new development is will have toresonant ringl is investigated for good energy-saving. And BBU

be done because there is no accelerator having such a specification in
the world. It is a necessary for that purpose to construct a test linac

important in the case of acceleration of high current beam, so it isnecessary to study the problem of induced higher electric field

which accelerates high intensity electron beam. For, in studying aboveproblems, an electron linac is better than others because of its cheap

modes caused by beam-RF interaction.

associated with the periodic structure of accelerating cavity is also

2 High power klystroncost. So we are now having a plan of constructing a CW linac
accelerating 10 MeV-lOOmA electrons with duty factor 20% for basic
technical research and development. This R&D will be carried out-358-

There is no CW klystron that output power over 1 MW in theworld. So new development especially for electron gun, collectorand output window is needed for stable running of accelerator.

ReferenceHigh conversion efficiency of electricity into RF is also important.
At present, our goal is to get 65% efficiency.
1. I. Sato et

3 Analysis of thermal stress of accelerating tubeal.

to be published in PAR TIC L E

ACCELERATORS.

The thermal stress by micro-wave that power amount to 300kW
per tube is serious for deformation of cavity structure. For thisproblem, some simulation calculation and model experiments mustbe .achieved in order to search and examine enough cooling(MeV)

Beam energystructure.
Conclusion
Proposal of constructing 1OMe V-1 OOmA test linac for incineration
disposal was mentioned. There are many subjects for high intensity
beam acceleration and good energy saving.Main design items in thisMax beam current

(rnA)

100

Av. beam current

(rnA)

20

Duty factor(%)

20Tab. 1. Basic structure of the test linac

fiscal year is presented for development of the test linac.

D.
'QJ~10a..

1c0'-t 10°

QJ
r-1@ 000&'3~~~~~

0oO CID0000w00

oo1010 X 10-4

Energy resolution

0Electron Energy (MeV)
Fig. 1. The status of electron accelerators.
Triangle sign in this figure is a position of the test linac.

-359-

'v

~ ~;:. .-~_· -~~~-..

••••

L- ~ ·. ~~~~

Fig. 2. Conceptual bird view of the test linac facility.

-360-

•

~~

•-..

"--~~-:~~~·~