PSI Methodologies for Nuclear Data Uncertainty Propagation with CASMO-5M and MCNPX: Results for OECD/NEA UAM Benchmark Phase I

Table 5

Effect of changing the perturbation group structure for the PB-2 HZP cell case.

Parameter	Perturbation group structure
	19-group	31-group	44-group
Eigenvalue	0.55%	0.55%	0.54%
U-235 abs.	0.99%	0.99%	0.92%
U-235 fis.	1.01%	1.02%	0.94%
U-238 abs.	1.08%	1.07%	1.03%
U-238 fis.	3.70%	3.67%	3.73%