One group cross-sections

The solution of the diffusion equation 3.27 requires the knowledge of the one-group cross-sections. Some of the most important fission and capture cross-sections for heavy nuclei are given in the two following tables. Table 3.1 gives the cross-sections for a PWR spectrum while Table 3.2 gives the cross-sections for a fast reactor of the Super-Phenix type.

Z 92 92 94 94 94 94 94 93 96

A 235 238 239 240 241 242 243 243 244

fission 40.62 .107 101.02 .44 109.17 .28 .462 .092 .62

capture 11.39 1.03 42.23 109.39 37.89 57.55 11.51 72.257 29.261

TABLE 3.1

Fission and Capture cross-sections(barns) averaged over a PWR neutron spectrum[35]

Z	A	fission	capture
90	232	0.0137	0.444
91	233	0.	0.8
92	233	2.742	0.257
92	234	0.51	0.45
92	235	2.03	0.566
92	236	0.116	0.663
92	237	1.82	0.41
92	238	0.0428	0.296
93	237	0.36	0.765
93	238	3.1	0.36
93	239	0.36	0.828
94	238	1.38	0.211
94	239	1.85	0.503
94	240	0.354	0.415
94	241	2.49	0.432
94	242	0.278	0.342
94	243	2.03	0.568
94	244	0.28	0.34
95	241	0.463	0.300
95	241	0.463	0.300
95	242	1.83	0.403
95	243	0.237	0.555
96	241	3.25	0.210
96	242	0.42	0.38
96	243	0.32	0.4
96	244	0.412	0.373
96	245	2.45	0.4
96	246	0.3	0.302
96	247	2.15	0.362
96	248	0.293	0.306

TABLE 3.2

Fission and Capture cross-sections(barns)

averaged over a LMFBR neutron spectrum[35]