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)

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 4. Proposal of new X-band linac system

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 95-084. 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

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 300-700 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.

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

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

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

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

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 4. Proposal of new X-band linac system

EC – JRC – IRMM Institute for Reference Materials & Measurements

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 - 400 m) Measurement stations with special equipment to perform: Total cross section measurements Partial cross section measurements Mondelaers and Schillebeeckx, Notizario 11 (2006) 19

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

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

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 4.8×10^9(1/s)@Neutron Source exp Cold neutron By Prof. Kiyanagi, and Prof. Kino’s presentation

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 4. Proposal of new X-band linac system

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 : 1300.8 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 n/s @6kW

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)

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

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 4. Proposal of new X-band linac system

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

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.)）

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.

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.