TUNL Seminar

Lawrence Livermore National Laboratory LLNL-PRES-xxxxxx1

LLNL-PRES-XXXXXXThis work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract

DE-AC52-07NA27344. Lawrence Livermore National Security, LLC

Modernizing the Fission Basis: Measurement of Fission Product Yields from Fast-Neutron-Induced FissionTUNL Seminar

Anton Tonchev for the LLNL-LANL-TUNL collaboration

September 12, 2013

622876


TUNLDukeC. BHATIAM. BHIKEB. FALLINC. HOWELLW. TORNOW N.C. State Univ.M. GOODENJ. KELLEY

LLNLJ. BECKERR. HENDERSONJ. KENNEALLYR. MACRIC. RYANS. SHEETSM. STOYERA. TONCHEV

LANLC. ARNOLDE. BONDT. BREDEWEGM. FOWLERW. MOODYR. RUNDBERGG. RUSEVD. VIEIRAJ. WILHEMY

Acknowledgements


Outline

1. Motivation

2. Energy Dependence of Fission-Product Yields

3. Experimental technique

4. Results

5. Future plans


Motivation

Resolve the long-standing difference between LLNL and LANL with respect to selected fission product data

Joint LANL/LLNL fission product review panel endorsed a possible energy dependence of 239Pu(n,f)147Nd fission product yield with fission neutrons:

4.7%/MeV from 0.2 to 1.9 MeV (M. Chadwick)

3.2%/MeV from 0.2 to 1.9 MeV (I. Thompson)

Mostly low energy data from critical assembly or fast reactors

239Pu(n,f)147Nd

M.B. Chadwick et al. Nuclear Data Sheets 111 (2010) 2923; H.D Selby et al. Nuclear Data Sheets 111 (2010) 2891.P. Baisden et al, LLNL-TR-426165, 2010; R. Henderson et al. LLNL-TR-418425-DRAFT; I. Tompson et al. Nucl. Sci. Eng. 171, 85 (2012)

There are no 147Nd data between 1.9 and 14 MeV

Very scarce experimental data at the MeV-range

Large discrepancy (~20%) at 14 MeV


Nuclear Fission

Scissionpoint

0

10-17

85% KE10-20 10-15

Prompt n-emission

10-18

10-15

10-12

Prompt g-emission

Beta decay,

delayed n,g

10-6

10-9

Credit: Encyclopædia Britannica, Inc

Saddlepoint

Distance betw

een fragments (cm

)

time (s)


Mass DistributionP

re-a

ctin

ides

((e.

g.W

,Au,

Pb,

Bi)

Hea

vy(E

s to

Lr)

M

ediu

m(U

to C

f)

Asymmetric

Symmetric

Symmetric

Lig

ht(T

h, P

a )

Triple humped


Fission Fragment Distribution with Neutron Energy

YiE (A) = fractional yields of mass chain ‘A’ (after b decays) from initial

actinide ‘i’ for neutron energy ‘E’.

How does the asymmetry evolve with neutron energy for 235,238U, 239Pu?

Depends on actinide Depends on neutron energy

Goal: Develop high-precision FPY energy dependence from 1 to 15 MeV


Monoenergetic Neutron Sources available at TUNLDD, DT, PT, and PLi, Sources

DENIS source FN TANDEM 10MV

Shielded neutron source area

Flux on target (107 - 108) cm-2 s-1

Energy spread dE/E = 0.1 to 0.402H(d,n)3He; Monoenergetic neutrons: 4.0 – 7.7 MeV

3H(p,n)3He; Monoenergetic neutrons: 0.5 – 7.7 MeV

Quasi-monoenergetic neutrons

7Li(p,n)7Be; Monoenergetic neutrons: 0.1 – 0.65 MeV

3H(d,n)4He; Monoenergetic neutrons: 14.8 – 20.5 MeV


TUNL TOF Room


2H gas

From VdG accelerator

p or dn

One thick target ~0.2 g/cm2

Two thin targets ~10 μg/cm2

Dual fission chamber n-detector

Monoenergetic Neutron Irradiation


Dual Fission Chamber Measurements

Fission_counts = mf F σn,f εf tf

Gamma_counts (147Nd) = mγ F σn,f FPY Iγ εγ tγ

mγ ( mf) = atoms in the 239Pu thick (thin) target F = neutron flux (n.cm-2.s-1)

σn,f = 239Pu(n,f) fission cross section (cm2) FPY = fission product yield of 147Nd per 239Pu fission

Iγ = branching ratio of Eg εγ (εf) = counter efficiency of g-ray (fission) detection

tγ ( tf) = time factor for irradiation and counting periods of g-ray (fission)

(Gamma_count / Fission_count) = (mthick / mthin) * FPY * C

FPY = (Gamma_count) / Fission_count) * (mthin / mthick) * C


Error estimation on the FPY Measurements:

Relative FPY Ratio (This is what we have promised)

1. Statistical uncertainties of g-ray peak counts (1-2%)2. Relative HPGe detector efficiency (1-2% including the fit)

Absolute FPY energy dependency:

1. Statistical error of g-ray peak counts (1-3%)2. Absolute detector efficiency (2% including the fit)3. Branching ratios (0.2 – 8% (147Nd))4. Absolute FC efficiency (3% experimentally, 0.5% simulation)5. Low energy neutrons (<1%)6. Neutron fluence rate fluctuation (<0.3%)7. Efficiency conversion ratio between close and standard geometry (<1%)8. True coincidence summing (<1%)9. Random coincidence summing (<0.2%)10. Sample weight (<0.1%)11. Self-absorption of g-ray (0.1 - 1%)


Need to know?

Room returns neutrons – at ToF area

ToF spectrum from neutron and 3He monitors

Fission chamber design and characteristics


Room Return Neutrons: Why are they Important?

Region of interest

Not desirable events in our measurements


Room return neutron study with 16 different off-axis foils in ToF area

Reactions studied115In(n, n')115mIn197Au(n, 2n)196Au27Al(n, a)24Na235U (n, f) 133I and 135I

Room return neutrons ~ 105 times smaller than primary flux on target


Need to know?





ToF spectrum from 0-degree neutron monitor at En=9.0 MeV

Neutron and gamma are well separated

Break up – Negligible


Need to know?





Dual Fission Chamber: The Renaissance of the NIST idea

Design and fabricate three fission chambers: one for 239Pu, one for 235U, and one for 238U

Dedicated thin (~10 μg/cm2) 235,238U and 239Pu foils electroplated on 0.5” titanium backing★

Dedicated thick (200 - 400 mg/cm2) 235U (93.27%) 238U (99.97%) and 239Pu (98.4%) targets

Fission chamber efficiency confirmed: 100%, confirmed with activation measurements

★ Made by LANL

Gas flow in and out

FC gas cell


Fission Spectrum at En = 9.0 MeV

Excellent a / fission separation

alpha

fission


Fission Chamber TOF at En = 9.0 MeV

in cadmium

without cadmium

9 MeV / Background neutrons = 150 / 1


Experimental Results


FPY Ratios to 99Mo for 239Pu at 4.6, 9.0, 14.5, and 14.8 MeV

FP/ 99Mo

Present

Data

Present

Data

Present

Data

Present

Data

Gindler 1

et al.

LANL2

Selby et al.

Saclay3

J. Laurec et al.

England 4 et al.

LANL5 LLNL6

Nethaway

<Einc> 4.6 MeV 9 MeV 14.5 MeV 14.8 MeV 4.5 MeV 1.3 -1.5 MeV 14.7 MeV 14 MeV 14 MeV 14.8 MeV

87Kr91Sr92Sr97Zr

105Ru131I

132Te133I

140Ba142La143Ce147Nd

0.21 ± 5.3%0.52 ± 2.2%0.56 ± 4.3%0.96 ± 3.3%0.96 ± 3.7%

-0.83 ± 5.2%1.18 ± 5.0%0.89 ± 3.8%

-0.63 ± 3.9%0.37 ± 5.1%

0.22 ± 5.3%0.48 ± 1.4%0.51 ± 3.7%0.89 ± 2.9%0.85 ± 2.2%0.93 ± 3.3%0.76 ± 4.0%1.03 ± 3.5%0.82 ± 3.0%0.80 ± 2.1%0.64 ± 2.6%0.34 ± 3.9%

0.22 ± 5.5%0.52 ± 1.4%0.52 ± 3.7%0.97 ± 2.1%0.86 ± 2.0%1.03 ± 3.0%0.80 ± 4.0%1.09 ± 3.9%0.84 ± 2.3%0.85 ± 2.0%0.64 ± 2.3%0.35 ± 3.2%

0.21 ± 5.3%0.53 ± 1.8%0.52 ± 3.8%0.86 ± 2.7%0.86 ± 2.7%

-0.76 ± 4.9%0.88 ± 3.7%0.85 ± 2.8%0.90 ± 3.4%

-0.36 ± 4.6%

0.22 ± 4.5%0.51 ± 4.8%0.58 ± 6.4%0.93 ± 0.6%0.87 ± 6.0%

-0.84 ± 0.7%1.11 ± 0.6%0.88 ± 0.6%0.79 ± 5.9%0.65 ± 0.6%

-

0.77 ± 4.5%

----

0.85 ± 4.2%

-0.71 ± 5.2%

0.34 ± 3.5%

---

0.83 ± 3.3%-

0.61 ± 3.5%0.81 ± 4.5%0.99 ± 6.2%0.82 ± 3.1%

-0.67 ± 3.2%0.31 ± 5.2%

--

0.93 -

0.920.700.940.78

-0.590.36

0.86 ± 7.1 %0.74 ± 6.0 %0.97 ± 5.2 %0.61 ± 7.9 %0.74 ± 5.7 %0.74 ± 5.8 %

-0.34 ± 6.3 %

0.86 ± 7.1 %--

0.6 ± 7.1%-

0.72 ± 7.1 %

-0.33 ± 7.1 %

1 J.E.Gindler et al. Phys. Rev. C 27 (1983) 2058.2 H.D.Selby et al. Nucl. Data Sheets 111(2010)2891-2922.3 J. Laurec et al. Nucl. Data Sheets 111(2010)2965-2980.4 T.R. England and B.F. Rider, LA-UR-94-3106.5 M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135–31526 D.R.Nethaway and B. Mendoza, Phys. Rev. C 6 (1972) 1827


FPY Ratios to 99Mo for 235U and 238U at 4.6, 9.0, and 14.5 MeV

FP/ 99Mo PresentData

PresentData

Present

DataGlendenin et al. 1

ANLSelby et al. 2

LANLLaurec et al. 3

SaclayMaeck mass-spectrometry4

England et al.5

Innes et al. 6

LANLNethaway et

al.7

LLNL

<Einc> 4.6 MeV 9 MeV 14.5 MeV 3.9 MeV ~1.4 MeV 14.7 MeV 0.2-0.4 MeV 14 MeV 14 MeV 14.8 MeV238U

97Zr105Rh

131I132Te135Xe140Ba141Ce143Ce147Nd

0.86 ± 2.6 %0.55 ± 3.0 %

-0.74 ± 4.3 %

-0.79 ± 2.9 %

-0.70 ± 3.2 %0.35 ± 3.5 %

0.85 ± 2.4 %0.62 ± 3.3 %0.60 ± 2.7 %0.74 ± 4.5 %

-0.87 ± 2.8 %

-0.73 ± 3.1 %0.37 ± 2.8 %

0.97 ± 2.2 % 0.76 ± 3.4 %0.71 ± 2.2 %1.18 ± 5.4 %1.15 ± 3.4 % 0.93 ± 2.5 %0.88 ± 2.4 %0.87 ± 2.6 %0.40 ± 3.5 %

0.94 ± 0.2 %0.73 ± 0.4 %0.56 ± 0.2 %0.82 ± 0.3 %

-1.03 ± 0.5 %

-0.77 ± 0.4 %0.45 ± 0.4 %

----

0.92 ± 3.6 %--

0.42 ± 3.8 %

0.89 ± 3.4 %0.58 ± 5.0 %0.70 ± 3.4 %0.81 ± 4.7 %0.99 ± 4.8 %0.79 ± 3.3 %0.67 ± 3.5 %0.77 ± 3.2 %0.34 ± 5.4 %

-----

0.95 ± 2.4 %--

0.40 ± 1.8 %

0.930.570.690.811.020.880.530.700.37

0.89 ± 6.1 %0.57 ± 14.7 %0.71 ± 5.6 %0.82 ± 5.9 %

-0.80 ± 5.9 %

0.75 ± 5.9 % -

0.37 ± 5.6 %

0.88 ± 6.5 %----

0.78 ± 7.2 %-

0.86 ± 7.2 % 0.36 ± 7.0 %

235U 97Zr

105Rh131I

132Te140Ba143Ce147Nd

1.04 ± 4.4 %0.37 ± 2.5 %

-1.09 ± 4.6 %0.99 ± 3.6 %0.93 ± 3.8 %0.35 ± 4.3 %

1.04 ± 2.4 %0.39 ± 2.4 %0.91 ± 3.6 %1.08 ± 4.2 %1.05 ± 2.9 %0.93 ± 3.8 %0.30 ± 3.0 %

1.02 ± 1.8 %0.37 ± 1.8 %0.84 ± 2.4 %1.10 ± 3.3 %1.06 ± 2.5 %0.92 ± 2.6 %0.38 ± 2.7 %

1.09 ± 0.4 %-

0.73 ± 0.3 %0.94 ± 0.4 %1.07 ± 0.4 %0.86 ± 0.5 %0.41 ± 0.3 %

----

0.97 ± 3.3 %-

0.36 ± 3.4 %

0.98 ± 3.6 %-

0.86 ± 3.3 %0.81 ± 4.7 %0.89 ± 3.3 %0.72 ± 3.3 %0.30 ± 5.5 %

----

1.01 ± 1.4 %-

0.34 ± 1.4 %

1.010.360.800.790.880.740.32

0.99 ± 6.6 %0.37 ± 6.0 %0.89 ± 5.8 %0.81 ± 5.5 %0.89 ± 5.5 %

-0.32 ± 5.8 %

1 ± 13.9 %---

0.83 ± 10.6 %-

0.32 ± 11.9 %

1 L. E. Glendenin et al. Phys. Rev. C 24 (1981) 2600.2 H. D. Selby et al. Nucl. Data Sheets 111(2010)2891-2922.3 J. Laurec et al. Nucl. Data Sheets 111(2010)2965-2980.4 W.J. Maeck et al., ENICO – 1028 (1980).5 T.R. England and B.F. Rider, LA-UR-94-3106.6 M. Mac Innes, M.B. Chadwick, and T. Kawano, Nuclear Data Sheets 112 (2011) 3135–3152.7 D. R. Nethaway and B. Mendoza, Phys. Rev. C 6 (1972) 1827.


239Pu FPY Ratios to 99Mo: at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary

90 100 110 120 130 140 1500.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6 239Pu_TUNL

147Nd143Ce

140Ba

133I

132Te

131I97Zr

Mass Number of fission fragments

Yie

ld r

atio

( X

/ 9

9 Mo

) TUNL_4.6MeV TUNL_9MeV TUNL_14.5 MeV TUNL_14.8 MeV


235U FPY Ratios with Respect to 99Mo: Comparison Preliminary

90 100 110 120 130 140 1500.0

0.5

1.0

1.5

2.0

147Nd

143Ce

140Ba132Te

131I

105Rh

97Zr

235U Y

ield

rat

io (

X /

99 M

o )


TUNL_9 MeV LA-UR-94-3106_14MeV Saclay_14.7 MeV LANL_1.3-1.5 MeV


238U FPY Ratios with Respect to 99Mo: Comparison Preliminary

90 100 110 120 130 140 1500.0

0.5

1.0

1.5

147Nd

143Ce

140Ba132Te

131I

105Rh

97Zr

238UY

ield

rat

io (

X /

99 M

o )


TUNL_9 MeV LA-UR-94-3106_14MeV Saclay_14.7 MeV LANL_1.3-1.5 MeV


239Pu FPY Ratios: 147Nd/99Mo at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary

0 2 4 6 8 10 12 14 160.20

0.25

0.30

0.35

0.40

0.45

0.50

En (MeV)

FPY COMPARISON_239Pu14

7 Nd

/ 99M

o

TUNL Selby_LANL(2010) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)


239Pu FPY Ratios: 140Ba/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary

0 2 4 6 8 10 12 14 160.0

0.2

0.4

0.6

0.8

1.0

1.2

En (MeV)


0 Ba

/ 99M

o

TUNL Gindler_ANL(1983) Selby_LANL(2010) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)


239Pu FPY Ratios: 97Zr/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary

0 2 4 6 8 10 12 14 160.0

0.2

0.4

0.6

0.8

1.0

1.2

En (MeV)


Zr

/ 99M

o

TUNL Gindler_ANL(1983) Selby_LANL(2010) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)


147Nd Absolute Fission Product Yield Preliminary






Comparison with Theory

1. Our absolute magnitude of the 147Nd FPY below 2.5 MeV and at 14.5 MeV neutron energies are slightly higher than the predicted values.

2. We can rule out the two low-yield data at 14.8 MeV.

3. The slope of 147Nd FPY from 4.6 to 14.8 MeV is slightly negative (-1% / MeV).

4. There is no energy dependence (or it is below our experimental sensitivity) for 140Ba and 99Mofragments.

Model calculation ___Uncertainties ___

J. Lestone. Nuclear Data Sheets 112 (2011) 3120


SummaryWe start delivering precise (< 2% relative uncertainty) information on FPY ratios obtained at SIX energies in case of 239Pu and at FOUR energies for 235U and 238U

We will deliver accurate (4-5% absolute uncertainty) information on the energy dependent fission product yields covering an energy range from 1 < En < 15 MeV

Potential experiments:

Reduce 147Nd branching ratio uncertainty from the current 8%

High-accuracy measurements in the 0-2 MeV range to clarify 144Ce and 147Nd neutron-energy dependence

Strong LLNL-LANL-TUNL Collaborative Effort


Additional Slides


Further Experiment & Theory NeededFuture experiments (2013 – 2015):

Reduce 147Nd branching ratio uncertainty from the current 8% (submitted LLNL LDRD proposal)

Developing a high-intensive 7Li(p,n) neutron source at TUNL

High-accuracy measurements in the 0-2 MeV range to clarify 147Nd neutron-energy dependence using 7Li(p,n) and 3H(p,n) reactions

Two measurements at the both sides of the 2nd chance fission, i.e. En = 5 and 7 MeV

Thermal measurement at the MIT reactor

Potential theory work:

Guidance on shape from onset of 2nd-chance fission


Summary of identified fragments for 235U, 238U and 239Pu

Fragment Eg (keV)' T1/2 Ig %

95Zr 756.725 12 64.032 d 6 54.38 % 2297Zr 743.36 3 16.749 h 8 93.09 % 16

105Rh 318.9 1 35.36 h 6 19.1 % 6127Sb 685.7 5 3.85 d 5 36.8 % 2

131I 364.489 5 8.0252 d 6 81.5 % 5132I 954.55 9 1.387 h 15 17.6 % 5

132Te 228.16 6 3.204 d 13 88 % 3133I 529.872 3 20.83 h 8 87.0 % 23

135Xe 249.794 15 9.14 h 2 90 % 3140Ba 537.261 9 12.7527 d 23 24.39 % 22141Ce 145.443 34 32.508 d 1 48.29 % 20143Ce 293.266 2 33.039 h 6 42.8 % 4147Nd 531.016 22 10.98 d 1 13.37 % 11


Extra Slides


Extra Slides


239Pu FPY Ratios: 147Nd/99Mo at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary


239Pu FPY Ratios: 147Nd/140Ba at 4.6, 9.0, 14.5 and 14.8 MeV Preliminary


239Pu Fission chamber spectra at En = 14.5 MeV



239Pu FPY Ratios: 132Te/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary

0 2 4 6 8 10 12 14 160.0

0.2

0.4

0.6

0.8

1.0

1.2

En (MeV)

FPY COMPARISON_239Pu

132 T

e / 99

Mo

TUNL Gindler_ANL(1983) Laurec_Sachlay(2010) England(1994) Innes_LANL(2011) Nethway_LLNL(1972)


239Pu FPY Ratios: 143Ce/99Mo at 4.6, 9.0, 14.5, and 14.8 MeV Preliminary

0 2 4 6 8 10 12 14 160.0

0.2

0.4

0.6

0.8

1.0

En (MeV)


3 Ce

/ 99M

o

TUNL Gindler_ANL(1983) Selby_LANL(2010) Laurec_Sachlay(2010) England(1994)


What We Have Done so Far

1. Precise FPY measurements on 239Pu, 235U and 238U En = 1.5, 2.6, 4.6, 9.0, 14.5, and 14.8 MeV

2. From September 2011 to April 2013:

Total beam on target ~ 1000 hours

Funded by NNSA AA (Multiply by ~$300 / h)

3. Counting time at TUNL: more than a year of continuous fission products measurement


Reducing fission-product g-ray branching-ratio uncertainties

147CeQb=3.4 MeV

56.4 sIY: 1.91%

147PrQb=2.7 MeV

13.4 mIY: 0.18%

147NdQb=0.9 MeV

10.98 dIY: 0.001%

b-

b-

b-

Produce pure sources using mass-separated CARIBU fission-product beam…

(DM/M~10-4… only need DM/M~10-2)(1010 atoms after 1 day)

…collaborate with TAMU for high-precision b and g-ray spectroscopy

At TAMU, they have a unique HPGe detector laboriously calibrated to ~0.2% for efficiency

count b decays with low-threshold 4p b counter (~100% efficient for bs)

N. Scielzo: ER-LDRD proposal

TUNL Seminar

Documents

fission basis

fission neutrons

f147nd fission product

fission fragment distribution

low energy data

department of energy

possible energy dependence

nuclear data sheets