Cross-section adjustment methods based on minimum variance unbiased estimation

Figures & data

Table 1. Calculation results of the variance-covariance matrix traces.

		EA-MVUE	CA-MVUE	RA-MVUE
Target core parameters^1	Rigorous	0.02386*	0.02405	42.57
	Simplified	0.02386	0.02405	42.57
Adjusted cross-section set^2	Rigorous	133.1	4.213*	1.269 × 10^5
	Simplified	4.195	4.195	1.269 × 10^5
Integral experimental quantities^3	Rigorous	1.425	0.9182	0.3922*
	Simplified	0.9209	0.9182	0.3922

1: $\sqrt{\mathrm{tr}\left(\mathrm{Var}\left({\mathbf{R}}_c^{\left(2\right)}\left({\mathbf{T}}_x\right)\right)\right)}$, 2: $\sqrt{\mathrm{tr}\left({\mathbf{M}}_x\right)}$, 3: $\sqrt{\mathrm{tr}\left(\mathrm{Var}\left({\mathbf{R}}_c^{\left(1\right)}\left({\mathbf{T}}_x\right)\right)\right)}$ where x is the method name,

*: the smallest trace among the rigorous EA-MVUE, CA-MVUE, and RA-MVUE.

Table 2. C/E values of the recalculated integral experimental quantities.

		EA-MVUE	CA-MVUE	RA-MVUE
ZPPR-9 KEFF^1	Rigorous	1.0022 ± 0.91%*	1.0005 ± 0.06%	1.0005 ± 0.06%
	Simplified	1.0009 ± 0.25%	1.0005 ± 0.06%	1.0005 ± 0.06%
ZPPR-9 CRW^2	Rigorous	1.0309 ± 4.42%	0.9904 ± 2.93%	0.9974 ± 0.99%
	Simplified	0.9904 ± 2.93%	0.9904 ± 2.93%	0.9974 ± 0.99%
ZPPR-9 SVR^3	Rigorous	1.0511 ± 7.79%	0.9971 ± 4.11%	1.0012 ± 1.59%
	Simplified	0.9980 ± 3.89%	0.9971 ± 4.11%	1.0012 ± 1.59%

¹Criticality, ²control rod worth, ³sodium void reactivity.

*Standard deviation.

Table 3. Correction factors of the predicted target core parameters.

		EA-MVUE	CA-MVUE	RA-MVUE**
750MWe KEFF^1	Rigorous	0.9984 ± 0.15%*	0.9980 ± 0.26%	–
	Simplified	0.9984 ± 0.15%	0.9980 ± 0.26%	–
750MWe CRW^2	Rigorous	0.9690 ± 1.45%	0.9691 ± 1.45%	–
	Simplified	0.9690 ± 1.45%	0.9690 ± 1.45%	–
750MWe SVR^3	Rigorous	0.9689 ± 1.89%	0.9685 ± 1.90%	–
	Simplified	0.9689 ± 1.89%	0.9685 ± 1.90%	–

¹Criticality, ²control rod worth, ³sodium void reactivity.

*Standard deviation, **no meaningful result available.

Figure 1. Cross-section alteration of Pu-239 capture.

Figure 2. Cross-section alteration of Pu-241 fission.