Neutron Production

in a Massive Uranium Spallation Target

L.Zavorka+c, J.Adam, A.Baldin, W.Furman, J.Khushvaktov, Yu.Kish+u,

V.Pronskikh+f, A.Solnyshkin, V.Stegailov, V.Tsoupko-Sitnikov,

S.Tyutyunnikov, R.Vespalec+c, J.Vrzalova+c, M.Zeman

Joint Institute for Nuclear Research, Dubna, Russiac Czech Technical University, Prague, Czech Republicu Uzhhorod National University, Uzhhorod, Ukraine

f Fermi National Accelerator Laboratory, Batavia, USA

V.ChilapCPTP «Atomenergomash», Moscow, Russia

P.Caloun, M.SuchoparNuclear Physics Institute, Rez, Czech Republic

P.Zhivkov

Institute for Nuclear Research and Nuclear Energy, Bulgaria

& colleagues of the “E&T-RAW” collaboration

QUINTA

«Energy and Transmutation of Radioactive Waste»

J.Adam, A.Baldin, A.Berlev, W.Furman, N.Gundorin, B.Gus’kov, M.Kadykov, J.Khushvaktov, Yu.Kish, Yu.Kopatch, E.Kostyuhov, I.Kudashkin, A.Makan’kin, I.Mar’in, A.Polansky,

V.Pronskikh, A.Rogov, V.Schegolev, A.Solnyshkin, V.Tsupko-Sitnikov, S.Tyutyunnikov, A.Vishnevsky, N.Vladimirova, A.Wojciechowski, R.Vespalec, J.Vrzalova, L.Zavorka, M.Zeman

Joint Institute for Nuclear Research, Dubna, Russia

V.Chilap, A.Chinenov, B.Dubinkin, B.Fonarev, M.Galanin, V.Kolesnikov, S.SolodchenkovaCPTP «Atomenergomash», Moscow, Russia

M.Artyushenko, V.Sotnikov, V.VoronkoKIPT, Kharkov, Ukraine

A.Khilmanovich, B.MarcynkevichStepanov IP, Minsk, Belarus

K. Husak, S.Korneev, A.Potapenko, A.Safronova, I.ZhukJIENR Sosny near Minsk, Belarus

M.Suchopar, O.Svoboda, V.WagnerINP, Rez near Praha, Czech Republic

Ch. Stoyanov, O.Yordanov, P.ZhivkovInstitute of Nuclear Research and Nuclear Energy, Sofia, Bulgaria

M.Shuta, E.Strugalska-Gola, S.Kilim, M.BieleviczNational Centre for Nuclear Research, Otwock-Swerk, Poland

S.Kislitsin, T.Kvochkina, S. ZhdanovInstitute of Nuclear Physics NNC RK, Almaty, Kazakhstan

M. ManolopoulouAristotle Uni-Thessaloniki, Thessaloniki, Greece

W.WestmeierGesellschaft for Kernspektrometrie, Germany

R.S.Hashemi-NezhadSchool of Physics, University of Sydney, Australia

Motivation

1990s

1978

2011-2015

2016 ?

E&T-RAW

J.W.Weale, et al.,Journal.of Nucl.Ene.,A&B 14 (1961) 91.

Y. Kadi, A.H-Martinez NIM A 562 (2006) 573.

S. Andriamonje, et al., Phys.Lett.B 348 (1995) 697

Introduction

• The main aim of the E&T-RAW research:

• Investigation of electronuclear

production of neutrons for nuclear

energy generation and transmutation of

spent nuclear fuel in the deep subcritical

Accelerator Driven Systems (ADS)

• Attention has been focused on core with

maximally hard neutron spectrum

4

Hard neutronspectrum

• Transmutation of long-lived actinides

and fission products (FP) into short-

lived or stable isotopes

• (n,g)

• (n,f)

• (n,xn)

510-13 10-11 10-9 10-7 10-5 10-3 10-1 101

10-4

10-3

10-2

10-1

100

101

102

103

104

237Np Cross Sections

Cro

ss s

ectio

n (b

)

Neutron energy (GeV)

(n,f) (n,g) (n,2n)

Introduction

• A recently introduced scheme of subcritical

ADS with a hard spectrum has been called

• Relativistic Nuclear Technology (RNT)

deep subcritical natural (depleted)

uranium/thorium core

spent nuclear fuel elements

high-temperature helium coolant

minimal neutron leakage

Energy of incident particles Ep,d ~ 10 GeV6

Crucial point in RNT:

Beam energy

A. Krása, et al. NIM A (2010)

• ø 10 x 100 cm lead target

• compilation of experimental

data + new measurement

• maximum neutron production

around the beam energy 1 GeV

V.Yurevich, et al. PPN (2006)

• ø 20 x 60 cm lead target

•Kinetic energy of neutron

radiation Ekin and mean neutron

energy < En > grow

•Energy W spent on neutron

production increases as well

Ed

(GeV)

< En >

(MeV)

W/Ed

(%)

1.03 6.5 32.6

1.98 7.9 43.9

3.76 10.4 45.7

STILL

Optimal beam energy for ADS: OPEN7

Neutrons at higher energies

• Considerable increase in average

multiplicity of prompt-fission neutrons

up to En = 200 MeV

0 20 40 60 80 100 120 140 160 180 200

2

4

6

8

10

12

14

16

J.Taieb,+ 14215001 J.Frehaut,+ 20490001 J.Frehaut,+ 21685001 T.Ethvignot,+ 13964001 I.Asplund-Nilsson,+ 20075001

Prom

pt n

eutr

on y

ield

(pp

f)

Neutron energy (MeV)

238U

EXFOR:

8

• Prompt-fission

neutron average

kinetic energy

(Watt spectrum)

increases as well

(20% higher at En = 200 MeV)

Fundamental requirement:

• Monte Carlo

simulation tools:

9

10-11 10-9 10-7 10-5 10-3 10-1 10110-6

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

R = 30 mm

2 AGeV R30

4 AGeV R30

2 AGeV R120

4 AGeV R120

Neu

tron

flu

x (c

m-2G

eV-1∙d

eute

ron-1

AG

eV-1)

Neutron energy (GeV)

R = 120 mm

MARS15• Increase in:

• Neutron multiplicity due to (n,xn)

• Mean neutron energy f(Ebeam)

• Average kinetic energy f(En)

• Neutron yield f(En)

• Decrease in:

• Neutron production per

one proton above 1 GeV

Maximum hard

neutron spectrum

Experimental investigation

at the quasi-infinite target

RNT Research @ Dubna

• Central part of the quasi-infinite uranium

target QUINTA has been studied since 2010

• 512 kg set-up of metallic natural uranium

irradiated by deuteron beams of energy

from 0.5 AGeV up to 4 AGeV

• Experimental investigation of neutron

spectrum and transmutation of actinides

• Beam power gain approx. 2

• Calculated neutron leakage 80%

10

QUINTA target assembly

11

QUINTA target@JINR Nuclotron

512 kg natU December 2013

30 cm

12

Deuteron beam: (Al, Cu monitors)

Ed = 2 AGeV 2.12(3)1013 particles

Ed = 4 AGeV 6.08(6)1012 particles

Activationsamples

• Natural uranium

• Enriched uranium

• 235U and 238U

• Reactions: 235,238U(n,f) 238U(n,g)239Pu 238U(n,2n)237U13

0.72%

99.28%

Natural uranium

95.17%

4.83%

238U 235U

Enriched uranium

Crosssections

10-10

10-8

10-6

10-4

10-2

100

102

104

10-3

10-2

10-1

100

101

102

103

104

105

Cro

ss s

ecti

on

(b

)

Neutron energy (MeV)

235

U(n,f)

238

U(n,f)

238

U(n,g)

238

U(n,2n)

JENDL-HE/2007

TENDL 2013

TALYS 1.6

Followed by two b- decays

Experimental methods

• Activation measurement technique

• Gamma spectroscopy with the use of

HPGe detectors Canberra and ORTEC

(20%, resp. 30% relative efficiency)

Calibrated with standards made in 2013;

Efficiency compared with MC simulation

14

Isotope identification

• Half-life (min. 6 measurements)

• Energy and intensity of gamma line

• Reaction rates calculated

from measured activity

• Included corrections:

decay during irradiation, cooling and measurement, dead

time, detector efficiency, nonlinearity, beam instability,

gamma line intensity, self-absorption, gamma coincidence

summing, nonpoint-like source

15

Results on 238U(n,2n) 238U(n,g)

Radial production after section № 2

16

0 20 40 60 80 100 1200

100

200

Rea

ctio

n R

ate

(1E-2

8∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

238U(n,2n)237U

0 20 40 60 80 100 120

200

300

400

500238U(n,g)239Pu

Rea

ctio

n R

ate

(1E-2

8∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

Results on 238U(n,2n) 238U(n,g)

Radial production after section № 4

17

0 20 40 60 80 100 1200

20

40

238U(n,2n)237U

Rea

ctio

n R

ate

(1E-2

8∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

0 20 40 60 80 100 120

120

140

160

180

200

220

240

238U(n,g)239Pu

Rea

ctio

n R

ate

(1E-2

8∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

Results on 238U(n,2n) 238U(n,g)

(n,2n)/(n,g) spectral indices

18

0 20 40 60 80 100 1200.0

0.1

0.2

0.3

0.4

0.5

after 2nd section

Spec

tral

inde

x (n

,2n)

/(n,g)

(-)

Radius (mm)

2 AGeV 4 AGeV

0 20 40 60 80 100 1200.00

0.05

0.10

0.15

0.20

0.25

Spec

tral

inde

x (n

,2n)

/(n,g)

(-)

Radius (mm)

2 AGeV 4 AGeV

after 4rd section

Results on 238U(n,2n) 238U(n,g)

Longitudinal production

19

200 300 400 500 600 7000

100

200238U(n,2n)237U

Rea

ctio

n R

ate

(1E-2

8∙A

GeV

-1)

Longitudinal distance (mm)

2 AGeV 4 AGeV

200 300 400 500 600 700

100

200

300

400

500238U(n,g)239Pu

Rea

ctio

n R

ate

(1E-2

8∙A

GeV

-1)

Longitudinal distance (mm)

2 AGeV 4 AGeV

Fission rate in 235U and 238U

20

80 90 100 110 120 130 140 1501E-28

1E-27

1E-26

1E-25

Enriched uranium Central region Periphery

Rea

ctio

n ra

te

Mass number

a)

80 90 100 110 120 130 140 1501E-28

1E-27

1E-26

1E-25

Central region Periphery

Rea

ctio

n ra

te

Mass number

b) Natural uranium

80 90 100 110 120 130 140 150

2.0E-25

4.0E-25

6.0E-25

8.0E-25

1.0E-24

1.2E-24

Enriched uranium

c)

Rea

ctio

n ra

te /

Yie

ld

Mass number

Central region Periphery

80 90 100 110 120 130 140 150

2.0E-26

4.0E-26

6.0E-26

8.0E-26

2.0E-25

1.0E-26

1.0E-25

Natural uranium

d)

Rea

ctio

n ra

te /

Yie

ld

Mass number

Central region Periphery

ENDF/B-VII.1CUMULATIVE

YIELDS87Kr88Kr91Sr92Sr95Zr97Zr

99Mo103Ru105Ru129Sb

131I133I135I

140Ba143Ce

147Nd149Nd

Results on 235U(n,f) 238U(n,f)

Radial distribution after section № 2

21

0 20 40 60 80 100 120

15

20

25

30

35

40

45

50

z = 254 mm

235U

Rea

ctio

n ra

te (

1E-2

6∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

0 20 40 60 80 100 120

1

2

3

4

5

6

7

8

z = 254 mm

238U

Rea

ctio

n ra

te (

1E-2

6∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

Results on 235U(n,f) 238U(n,f)

Radial distribution after section № 4

22

0 20 40 60 80 100 1208

10

12

14

16

18

20

z = 516 mm

235U

Rea

ctio

n ra

te (

1E-2

6∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

0 20 40 60 80 100 120

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

z = 516 mm

238U

Rea

ctio

n ra

te (

1E-2

6∙A

GeV

-1)

Radius (mm)

2 AGeV 4 AGeV

Results on 235U(n,f) 238U(n,f)

Relative contribution of 235U(n,f) to natU(n,f)

23

0 20 40 60 80 100 120

3

4

5

6

7

8

9

10

11

z = 254 mm

235U in natU

Rel

ativ

e fiss

ion

of 23

5 U in

nat U

(%

)

Radius (mm)

2 AGeV 4 AGeV

0 20 40 60 80 100 120

3

4

5

6

7

8

9

10

11

z = 516 mm

235U in natU

Rel

ativ

e fiss

ion

of 23

5 U in

nat U

(%

)

Radius (mm)

2 AGeV 4 AGeV

Results on 238U(n,2n) 238U(n,g)

24

200 300 400 500 600 700

3

4

5

6

7

235U in natURel

ativ

e fiss

ion

of 23

5 U in

nat U

(%

)

Longitudinal distance (mm)

2 AGeV 4 AGeV

Longitudinal relative contribution of 235U(n,f) to natU(n,f)

Conclusion

• Radial and longitudinal distribution of (n,2n)

and (n,g) reaction rates in 238U and fission rates

in both 235U and 238U have been measured

• Results revealed a shift in the mean energy

of neutron spectrum towards higher energies

when increasing the deuteron beam energy

from 2 AGeV to 4 AGeV

• Contribution of 235U to the total fission rate

in natU was determined to be up to 10% in the

peripheral region of the QUINTA target and is

beam-energy-dependent

Future plans

• Experiments with BURAN (20t natU)

will be realized in the near future (2016)

• QUINTA @ Phasotron Ep = 660 MeV:

• Neutron spectrum measurements with

a set of 235,238U, 232Th, Bi, Au, Y, Co, Al

monoisotope activation detectors

(unfolding of neutron spectra)

500 kg

20 tons

Collaboration is welcome

Thank you for

your attention

Experimental results on p-t-v

• Inverse peak-to-valley (p-t-v) ratio for 238U using 112Ag, 115Cd isotopes in valley0 2 4 6 8 10

100

101

102

103

104

112Pd 112Ag

Act

ivity

(s-1)

Time (days)

70 80 90 100 110 120 130 140 150 160

0

1

2

3

4

5

6

7143Ce

135I133I

131I

115Cd

112Ag

97Zr

Yie

ld (

%)

Mass number

150 MeV 100 MeV 50 MeV 1 MeV

91Sr

TALYS 1.4

238U• Mean neutron energy in dependence on mass distribution of fission products

Experimental results on p-t-v

0 20 40 60 80 100 1200.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

112 A

g in

vers

e pe

ak-t

o-va

lley

ratio

(-)

Radius (mm)

91Sr 97Zr 131I 133I 135I 143Ce

112Ag inverse peak-to-valley ratio

Ed = 2 AGeV

z = 516 mm

0 20 40 60 80 100 1200.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

112 A

g in

vers

e pe

ak-t

o-va

lley

ratio

(-)

Radius (mm)

91Sr 97Zr 131I 133I 135I 143Ce

112Ag inverse peak-to-valley ratio

Ed = 4 AGeV

z = 516 mm

0 20 40 60 80 100 1200.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

112 A

g in

vers

e pe

ak-t

o-va

lley

ratio

(-)

Radius (mm)

91Sr 97Zr 131I 133I 135I 143Ce

112Ag inverse peak-to-valley ratio

Ed = 2 AGeV

z = 254 mm

0 20 40 60 80 100 1200.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

112 A

g in

vers

e pe

ak-t

o-va

lley

ratio

(-)

Radius (mm)

91Sr 97Zr 131I 133I 135I 143Ce

112Ag inverse peak-to-valley ratio

Ed = 4 AGeV

z = 254 mm