1. February 6, 2014 CLIC Workshop 2014@CERN, Switzerland
“Review of electron linac based neutron sources for nuclear data study"
Mitsuru Uesaka (Nuclear Professional School, University of Tokyo), ○ Walter Wuensch (CERN)

2. CONTENTS
Necessity of more precise nuclear data for melt fuel analysis in Fukushima and design of ADS
S-band electron linac neutron system in Belgium, USA and Japan
L-band electron linac neutron system in Japan
Proposal of new X-band linac system

3. Research Background and Purpose
Hideo Harada (JAEA)
Research Background and Purpose
Debris in TMI-2 have been analyzed by INEL (USA).
EC and Canada also analyzed debris supplied by USA.
JAERI (JAEA) also analyzed debris obtained at 1991.
J. M. Broughton, et al., “A Scenario of the Three Mile Island Unit 2 accident”, Nucl. Technol. 87, 35 (1989).
H. Uetsuka, et al., “Gamma Spectrometry of TMI-2 Debris” (written in Japanese), JAERI-Research
Non-destructive measurement method of nuclear fuels in melted core hasn’t been developed yet.
Quantity of nuclear materials in melted cores which are generated in nuclear accident like Fukushima is measured by non-destructive and high accuracy methods

4. Conceptual Diagram of NRD Facility
Hideo Harada (JAEA)
Conceptual Diagram of NRD Facility
Accelerator for pulsed neutron generation
Neutron detector
n ～1012 n/sec
Gamma detector
Sample for NRTA
Sample for NRCA
Beam dump
By NRTA, 3-7 kg of small sized MF will be measured within 20 min.
(The 3-7 kg: a MF area of cm2 and a thickness of 10 g/cm2).
By NRCA, 30 g of MF including 109 Bq (mainly 137Cs) will be measured within 1 hour for each beam line.

5. TOF Measurement by Small Pulse Neutron Source
Hideo Harada (JAEA)
Flight path = 5 m for NRTA
A Rough Sketch of Prototype Neutron Resonance Densitometer

6. Typical NRTA Data of Nuclear Materials
Hideo Harada (JAEA)
Typical NRTA Data of Nuclear Materials
236U
239Pu
240Pu
241Am
243Am
242Pu
241Pu
145Nd
133Cs
238U
152Sm
238U
239Pu
235U
131Xe
238U
235U
235U
Transmission 2 4 6 8 10 20 40 1
Neutron Energy / eV
Behrens et al., Nucl. Techn. 67 (1984) 162

8. Precision of nuclear data
keVからMeVにわたってデータが必要な事を口頭で伝える
これはADS用のデータ

9. Neutron TOF facility for nuclear data measurements
Reference
Beam
energy
Beam power
n Intensity
Beam pulse width
Pulse per sec
Flux
IRMM, GELINA
ND2007, p.563
Electron
100 MeV
6 kW
1 ns
800 Hz
@ 12 m
ORNL, ORELA
ND2007, p.441
180 MeV
5 kW
1013 n/s
8 ns
525 Hz
@ 40 m
Kyoto, e Linac
ND2007, p.591
30 MeV
1 kW
100 ns
100 Hz
@ 10 m
CERN, n-TOF
ND2007, p.537
Proton
20 GeV
9 kW
1015 n/s
6 ns
0.4 Hz
4×105 n/cm2/s
@ 185 m
LANL, Lujan
ND2007, p.415
0.8 GeV
80 kW
135 ns
20 Hz
@ 20 m
J-PARC, MLF
(Expected)
3 GeV
1 MW
～1017 n/s
～100 ns
25 Hz
～109 n/cm2/s
@ 22 m 9

11. CONTENTS
Necessity of more precise nuclear data for melt fuel analysis in Fukushima and design of ADS
S-band electron linac neutron system in Belgium, USA and Japan
L-band electron linac neutron system in Japan
Proposal of new X-band linac system

12. EC – JRC – IRMM Institute for Reference Materials & Measurements

13. TOF - Facility GELINA (10 meV < En < 20 MeV)
FLIGHT PATHS SOUTH
FLIGHT PATHS NORD
ELECTRON LINAC
TARGET HALL
Pulsed white neutron source
(10 meV < En < 20 MeV)
Neutron energy : time – of – flight (TOF)
Multi-user facility: 10 flight paths (10 m m)
Measurement stations with special equipment to perform:
Total cross section measurements
Partial cross section measurements
Mondelaers and Schillebeeckx, Notizario 11 (2006) 19

17. Hokkaido University 45 MeV electron linac
Neutron room 1m
6.4m
1.96m
21.1m
Target room
Target room + LINAC =42.5 m
45 MeV LINAC
Electron energy
~45MeV (gun current　~50mA）
~30 MeV（gun current~210ｍA）
Electron current
Average （example, 60μA　pulse width 3μs)
Pulse rate
10～100p.p.s(variable、single pulse） 17

18. Performance of Hokkaido University 45 MeV electron linac
S-band electron linear accelerator
Maximum energy:45 MeV
Maximum current: 140μA
Repetition: single 10pps~200pps
Pulse width: 10ns ~3μs
The electron beam is transported to the target room.
RIGHT: Pulsed cold neutron source
CENTER: Pulsed thermal neutron source, electron beam irradiation
LEFT: Fast neutron experiments

19. Typical Neutron and Photon Source
• 2mm thick lead radiator
• Electron Beam Energy = 25 MeV
• Pulse Width = 0.2 μs
• Rep.rate = 50 pps
• Electron beam current = 2 μA
Intensity 20~30MeV ~1012 (1/s)
Bremsstrahlung photon
PHITS
Simulation
Intensity of neutrons
Below 25.3meV 1.0×103 (1/cm2/s)
@L=6m
Source
exp
Cold neutron
By Prof. Kiyanagi, and Prof. Kino’s presentation

20. CONTENTS
Necessity of more precise nuclear data for melt fuel analysis in Fukushima and design of ADS
S-band electron linac neutron system in Belgium, USA and Japan
L-band electron linac neutron system in Japan
Proposal of new X-band linac system

21. Present status of KURRI-L-band Linac
Research Reactor Institute,
Kyoto University
Jun-ichi Hori
・Specification of injector
electric gun : YU-156(EIMAC)
incident voltage : 100kV DC, incident current : Max 10A
・Specification of RF driver
output : 3kW, frequency : MHz
・Energy of electron for neutron generation ： ～30 MeV
・Peak current : ～5A (short pulse) 2～100ns width
～0.5A(long pulse) 0.1～4 ms width
・Frequency：1～300 Hz (short pulse)
1～100Hz (long pulse)
・Neutron target : Ta with H2O moderator
・Power on target : Maximum 6 kW (200mA, 30MeV)
・Electron beam diameter on target : 1 cm
・Neutron production : ～8×1012

22. Injector and accelerator tubes
Target room
Water moderator in Al case
Ta target
Ta target and water moderator (Type-1)
Ta target and water moderator (Type-2)

23. 2. Flight path Flight tube : 2 lines Flight path : 10.0, 12.7, 24.2 m
Target room
Ta target
Flight tube : 2 lines
Flight path :
10.0, 12.7, 24.2 m
Measurement room at 10m
Measurement room at 24m
Measurement room at 12.7m
Control room
Cooling tower
Lead spectrometer
Experimental room

25. CONTENTS
Necessity of more precise nuclear data for melt fuel analysis in Fukushima and design of ADS
S-band electron linac neutron system in Belgium, USA and Japan
L-band electron linac neutron system in Japan
Proposal of new X-band linac system

26. TOF (Time-Of-Flight) system for nuclear data measurement
Ce:LiCAF
電子ビーム
レーザー X 線
X-ray
Laser

27. Existing X-band 30 MeV electron linac will be moved for neutron source
More than 10 m TOF
planning area
5 m TOF
planning area
電子ビーム
レーザー X 線
More than 40 m TOF
planning area
30 MeV X-band Linac
70 cm accelerator tube
Klystron and power
source are set
around the reactor
20 keV electorn gun + 5 MeV buncher+30 MeV structure
+ Neutron target
Peak Beam current: 250mA (Beam energy: 30MeV・Pulse width: 1μsec)
Beam Power: 0.375kW (50pps)
（S-band 30MeV⇒1kW(Hokkaido Univ.)）

28. S-band vs X-band Electron Energy: Both are available
Charge per microbunch: X is ~1/10
Bunches for RF pulse: X is 3~4 times
Charge and Peak Current per RF pulse and Average Current/Power: S is higher by ~2.
However, X-band 6 MW 400Hz Klystron is
under development so that the current/power
becomes closer.
Size: X is smaller.
Price is linear to Beam Power, maybe.

29. Thank you for your attention.
Summary
Several L/S-band electron linac neutron sources are operating for nuclear data study in the world.
Precision of nuclear data must be improved for Fukushima accident analysis and design of new nuclear system such as ADS.
New X-band electron linac neutron source is proposed and under construction at University of Tokyo.
Almost all L/S-band systems are older than 40 years and it is the time of renewing.
Due to compactness of X-band system, it can be installed in existing shielding facilities. Even its intensity is expected to be upgraded by new X-band high rep rate klystron.
Thank you for your attention.