Design of the Online Gross γ Monitoring Instrument at the Exit of the Helium Purification System in HTR-PM

Table 3

Monte Carlo simulation results of selected nuclides.

Nuclides	Average pulses emitted by the detector over the entire spectrum (100–3000 keV); (count/particle)	Average pulses emitted by the detector in the characteristic spectrum interval of Kr-88 (785–885 keV); (count/particle)	Estimated relative error	Estimated variance of the variance
Kr-85m	2.674E – 04	0.00E + 00	0.0273	0.0007
Kr-87	4.102E – 04	7.00E – 06	0.0221	0.0005
Kr-88	4.302E – 04	1.28E – 05	0.0216	0.0005
Kr-89	4.050E – 04	7.20E – 06	0.0222	0.0005
Xe-133	2.738E – 04	0.00E + 00	0.0270	0.0007
Xe-133m	3.194E – 04	0.00E + 00	0.0250	0.0006
Xe-135	3.312E – 04	0.00E + 00	0.0246	0.0006
Xe-135m	3.760E – 04	0.00E + 00	0.0231	0.0005
Xe-137	3.700E – 04	2.00E – 07	0.0232	0.0005
Xe-138	3.948E – 04	2.60E – 06	0.0225	0.0005
I-131	3.536E – 04	0.00E + 00	0.0238	0.0006
I-132	4.040E – 04	3.00E – 06	0.0222	0.0005
I-133	3.804E – 04	5.80E – 06	0.0229	0.0005
I-134	4.084E – 04	3.16E – 05	0.0221	0.0005
I-135	4.344E – 04	1.52E – 05	0.0215	0.0005
Rb-88	4.488E – 04	7.00E – 06	0.0211	0.0004
Cs-138	3.616E – 04	0.00E + 00	0.0235	0.0006