Input Calibration and Validation of RELAP5 Against CIRCUS-IV Single Channel Tests on Natural Circulation Two-Phase Flow Instability

Table 6

Difference between calculated and experimental values, test I-2.

Parameters		Calib. input	Varied input parameters
			Tin; −1°C	Tin; +1°C	HL R; 0 kW	HL R; 0.4 kW	Kin; −25%	Kin; +25%
Oscillation period (%)		−0.46%	−5.59%	−17.00%	−3.82%	−8.40%	2.07%	−4.95%
Flow rate (%)	Average	0.21%	−4.76%	5.88%	−0.58%	−1.73%	1.94%	−3.11%
	Maximum	16.58%	24.70%	34.25%	23.42%	27.39%	20.18%	18.03%
	Minimum	26.38%	−4.04%	13.96%	16.60%	7.59%	27.26%	8.95%
Inlet riser temperature (°C)	Average	−0.41	−0.66	−0.11	−0.44	−0.55	−0.42	−0.43
	Maximum	−1.29	−1.50	−1.20	−1.25	−1.46	−1.29	−1.27
	Minimum	−0.62	−1.02	−0.11	−0.70	−0.77	−0.64	−0.62
Middle riser temperature (°C)	Average	−0.14	−0.51	−0.75	−0.24	−0.53	−0.19	−0.11
	Maximum	−1.26	−1.35	−0.80	−1.17	−1.27	−1.16	−1.27
	Minimum	0.47	0.13	−0.44	0.64	0.22	0.43	0.53
Outlet riser temperature (°C)	Average	−1.18	−2.14	−2.47	−1.53	−2.63	−1.12	−1.59
	Maximum	−1.46	−1.56	−1.04	−1.20	−1.55	−1.51	−1.33
	Minimum	−1.64	−3.06	−2.40	−1.95	−3.35	−1.70	−1.93
Inlet pressure (mbar)	Average	5.94	−3.60	2.61	5.63	−4.74	9.00	3.72
	Maximum	4.59	−2.78	1.00	8.44	−0.46	16.21	7.31
	Minimum	12.37	−4.10	−10.52	3.47	−8.11	21.66	−2.71

The values in bold are maximum and minimum values obtained in simulations.