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

Table 5

Difference between calculated and experimental values, test I-1.

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 (%)		27.13	39.75	9.21	−3.84	50.76	27.74	25.30
Flow rate (%)	Average	7.07	−1.16	10.03	3.27	−2.07	7.73	5.04
	Maximum	−4.27	−16.91	14.62	28.78	−40.38	−4.47	−0.09
	Minimum	31.65	28.41	47.90	30.72	35.73	32.57	31.67
Inlet riser temperature (°C)	Average	−1.23	−1.40	−0.75	−1.00	−0.82	−1.29	−1.15
	Maximum	−1.00	−1.01	−0.94	−0.87	−0.98	−1.07	−0.95
	Minimum	−0.37	−0.96	0.13	−0.95	0.91	−0.44	−0.46
Middle tiser temperature (°C)	Average	−0.23	−0.55	0.27	−0.30	0.24	−0.31	−0.21
	Maximum	0.05	0.00	0.18	0.38	−0.24	0.02	0.07
	Minimum	−0.38	−0.99	0.17	−0.24	0.29	−0.49	−0.41
Outlet riser temperature (°C)	Average	−1.21	−1.61	−0.56	−0.62	−0.98	−1.30	−1.17
	Maximum	0.31	0.35	0.29	0.22	0.29	0.30	0.28
	Minimum	−1.21	−1.85	−0.59	−0.48	−1.25	−1.33	−1.21
Inlet pressure (mbar)	Average	2.52	3.77	2.74	2.47	4.06	2.60	1.45
	Maximum	3.53	3.92	7.88	6.14	3.76	6.23	4.58
	Minimum	29.07	37.11	13.71	0.69	49.49	33.78	18.78

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