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Contribution to the verification of PFNS covariances against keff, eff

and dosimetry benchmarks

IAEA, 21-24, Oct. 2013

Ivo KodeliJožef Stefan Institute, Slovenia

ivan.kodeli@ijs.si

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Scope

• Evaluate critical and dosimetry experiments sensitive to prompt (and delayed) fission neutron spectra.

– Fast reactor k-eff and beta-eff benchmarks are studied to test and compare state-of-the-art of nuclear data and uncertainty codes;

– VENUS-3 and reactor pressure vessel dosimetry measurements.

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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Analysed benchmarks from ICSBEP and IRPhE

• SNEAK-7A & -7B: MOX fuel reflected by metallic depleted U. • Jezebel: bare sphere of 239Pu metal, 6.385-cm radius• Skidoo (Jezebel-23): bare ~98.1% 233U sphere;• Popsy (Flattop-Pu): ~20-cm natural U reflected 239Pu sphere;• Topsy (Flattop-25): ~20-cm natural U reflected 235U sphere;• Flattop-23: ~20-cm natural U reflected 233U sphere;• Big Ten: 10% enriched U with U-reflector, cylinder r=41.91cm,

h=96.428cm;• ZPPR-9: MOX core with sodium cooling, depleted U blanket.

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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Analysis of benchmarks from ICSBEP and IRPhE

• ONE-, TWO-, THREE-DANT (1D, 2D, 3D), PARTISN (double precission)

• ENDF/B-VII.0 33-group cross-sections (TRANSX)

• SUSD3D code for keff and eff sensitivity-uncertainty calculations (with increased precision),

• JENDL-4.0m, SCALE-6.0 and recent Talou FNS covariance matrices; two-block FNS covariances

• Impact of uncertainty in prompt (and delayed) fission spectra was evaluated.

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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Calulated & measured -eff

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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Sensitivity of keff and eff with respect to PFNS

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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PFNS covariances

Two-block

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013Talou

JENDL-4.0

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Uncertainties in keff & eff due to PFNS calculated using Talou, "two-block«, JENDL-4.0 & SCALE-6.0 PFNS covariances.

Uncertainty

(10-3 %)k-eff beta-eff

Two-block

JENDL-4.0

SCALE-6.0

Talou Two-block

JENDL-4.0

SCALE-6.0

Talou

SNEAK 7A

U-235 22 27 20 18 53 50 36 23

U-238 71 99 78 97 49 25 17 38Pu-239 261 288 264 180 572 523 414 304

Total 271 305 276 206 577 526 416 307

SNEAK 7B

U-235 41 49 37 32 78 71 51 31

U-238 109 150 119 146 36 46 18 79Pu-239 335 377 343 239 551 489 377 279

Total 354 409 364 281 557 496 381 292Jezebel Pu-239 292 367 343 637 820 774

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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Uncertainty

(10-3 %)k-eff beta-eff

Two-block

JENDL-4.0

SCALE-6.0

Talou Two-block

JENDL-4.0

SCALE-6.0

Talou

Skidoo U-233 106 121 97 212 106 91

Popsy

U-235 6 8 6 5 28 30 22 16

U-238 47 68 54 69 105 94 79 64Pu-239 302 371 348 242 100 172 45 174

Total 306 377 352 252 147 199 93 186

Flattop 23

U-233 167 180 156 218 304 227

U-235 5 7 5 16 17 13

U-238 41 58 46 53 45 36

Total 171 189 163 225 308 231

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

Uncertainties in keff & eff due to PFNS calculated using Talou, "two-block«, JENDL-4.0 & SCALE-6.0 PFNS covariances.

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Uncertainty

(10-3 %)k-eff beta-eff

Two-block

JENDL-4.0

SCALE-6.0

Talou Two-block

JENDL-4.0

SCALE-6.0

Talou

Topsy U-235 220 290 229 195 374 289

U-238 44 64 50 47 92 70

Total 224 279 234 201 385 297

Big-ten

U-235 456 575 441 360 43 200 132 195

U-238 189 273 217 281 218 400 307 476

Total 493 637 491 456 218 448 334 514

ZPPR-9

U-235 6 7 5 5 14 13 9 5

U-238 76 103 81 98 45 16 11 32Pu-239 331 371 332 235 706 639 520 375

Total 340 385 342 255 708 639 521 376

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

Uncertainties in keff & eff due to PFNS calculated using Talou, "two-block«, JENDL-4.0 & SCALE-6.0 PFNS covariances.

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SNEAK-7A: Sensitivity to keff and eff pcm235U: 650238Uf: 1480239Pu: 210240Pu: 270241Pu: 490

k-eff Sensitivity (%/%)

MAT elastic inelastic (n,f) (n,) del pmt

U-235 0.001 -2.10-4 0.037 -0.005 3.10-4 0.056

U-238 0.102 -0.017 0.087 -0.156 0.002 0.137

Pu-239 0.006 -0.001 0.540 -0.058 0.002 0.779

-eff Sensitivity (%/%)

MAT elastic inelastic (n,f) (n,) del pmt

U-235 -2.10-4 -0.001 0.052 -0.001 0.080 -0.025 0.055

U-238 -0.011 -0.151 0.276 -0.017 0.488 -0.233 0.255

Pu-239 -0.002 -0.012 -0.252 -0.006 0.402 -0.700 -0.298

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

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SNEAK-7A: Uncertainty in eff (TOTAL~3 %)

SNEAK-7A Uncertainty (%)

MAT. elastic inelast. (n,f) (n,) del pmt p

d TOTAL  

JENDL 4.0m  

U-235 ~0 0.017 0.074 0.004 0.218 0.006 0.050 0.044 0.23  

U-238 0.051 1.425 0.101 0.066 1.610 0.138 0.025 0.279 2.18  

Pu-239 0.008 0.120 0.074 0.018 1.529 0.122 0.523 0.091 1.63  

SUM 0.13 1.44 0.19 0.07 2.23 0.18 0.53 0.30 2.7  

COMMARA-2  

U-235 0.008 0.008 0.025 0.017 N/A 0.002 0.036 / 0.05  

U-238 2.515 2.595 0.144 0.045 N/A 0.270 0.017 / 2.62  

Pu-239 0.169 0.216 0.126 0.055 N/A 0.051 0.341 / 0.43  

SUM 2.52 2.60 0.19 0.07 N/A 0.28 0.35 / 2.6  

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013

Variance penalty: D.W.Muir, NIM-A 644(2011) 55-58

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SNEAK-7B: Uncertainty in eff (TOTAL~3 %)

JEF/EFF, NEA, Nov 2012

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U-235 fission spectra averaged detector cross-section (VENUS-3 benchmark)

Detector Measured WATT Kornilov_Maslov 2009

JENDL-3.3

ENDF/B-VII

Talou- 2013

Al27(n,)[mb]

0.706 0.742 ±11.1%

0.699 ±11.1%

0.732 ±14.2%

0.746 0.699±11.1%

Ni58(n,p)[b]

0.1085 0.1085 ±4.0%

0.1056 ±3.0%

0.1072 ±5.5%

0.1075 0.1051±2.8%

In115(n,n’)[b]

0.1903 0.1871 ±1.7%

0.1851 ±1.2%

0.1883 ±2.7%

0.1881 0.1855±1.3%

Normalisation: =0.983 !!?

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Uncertainties in calculated reaction rates (VENUS-3)

Pressure Vessel Detector

Uncertainty (%)RR Ratio

Talou / ENDF/B7Kornilov_Maslov 2009

WATT JENDL-3.3

Talou- 2013

Al27(n,a) 11.5 11.5 14.5 12.3 0.954

Ni58(n,p) 4.9 5.9 7.6 4.7 0.978

In115(n,n’) 2.8 3.3 5.2 2.8 0.982

Spectra were scaled by 1/0.983 to account for the normalisation

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Uncertainties in calculated RPV reaction rates (CPY900)

Pressure Vessel Detector

Uncertainty (%)RR Ratio

Talou / ENDF/B7Kornilov_Maslov 2009

WATT JENDL-3.3

Talou- 2013

Fe56(n,p) 6.0 6.8 8.7 5.9 0.977

Ni58(n,p) 5.7 6.5 8.1 5.6 0.978

Cu63(n,) 11.0 10.9 13.9 11.7 0.963

Np237(n,f) 2.8 3.7 5.0 2.7 0.983

U238(n,f) 3.7 4.6 6.0 3.5 0.981

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• Relatively simple method based on derivation of Bretscher’s (prompt k-ratio) eff expression was derived and implemented in SUSD3D code to evaluate the uncertainty in beta-effective due to the basic nuclear data. The method was applied to the fast benchmarks SNEAK-7A, -7B, Jezebel, Flattop, ZPPR-9, Big Ten…

• Prompt (and delayed) fission spectra play an important but not the main role in k-eff and beta-eff benchmark uncertainties. E.g. the total uncertainty in eff was found to be in general around 3%, with the uncertainty in fission spectra contibuting around 0.5-0.7%.

• Talou PFNS preliminary testing was done indicating normalisation problems. Only one (thermal) PNFS covariances.

I. Kodeli, Sensitivity and Uncertainty in the Effective Delayed Neutron Fraction (eff), Nucl. Instr.& Methods in Phy.Research A 715 (2013)70–78

Objectives / Conclusions

IAEA Meeting of CRP on PFNS,, 21-24, Oct., 2013