5.4.5. Table Look-Up for Steam Generators or Intermediate Heat Exchangers

Table look-ups for steam generators or intermediate heat exchangers are used when the behavior of these components is known from other sources or when the details of the temperature distributions within the components are not important for the case at hand. The user supplies a table of normalized temperature drops vs. time and also a table of elevation of the thermal center vs. time. The thermal center of the steam generator or intermediate heat exchanger is the point above which the circulating fluid is assumed to have the density corresponding to the inlet temperature and below which it is assumed to have the density corresponding to the outlet temperature.

The outlet temperature of the steam generator or intermediate heat exchanger is calculated from the inlet temperature by

(5.4-100)\[T_{\text{out}} \left( t \right) = T_{\text{in}} \left( t \right) + f \left( t \right) \left\lbrack T_{\text{out}} \left( t = 0 \right) - T_{\text{in}}\left( t = 0 \right) \right\rbrack\]

where \(f \left( t \right)\) is obtained by linear interpolation from the user-supplied table of temperature drops. Also

(5.4-101)\[f \left( t = 0 \right) = 1.0\]

For the table look-up steam generator there is an option in the code for the user to specify the steam generator outlet temperature directly instead of specifying the temperature drop. For this option the user supplies a table of steam generator outlet temperature vs. time.

The gravity head is calculated from

(5.4-102)\[\Delta p_{\text{gr}} \left( t \right) = \rho_{\text{in}} \left( t \right) g\left\lbrack z_{\text{c}} \left( t \right) - z_{\text{in}} \right\rbrack + \rho_{\text{out}} \left( t \right) g \left\lbrack z_{\text{out}} - z_{\text{c}} \left( t \right) \right\rbrack\]

where

\(\rho_{\text{in}} \left( t \right), \rho_{\text{out}} \left( t \right)\) = the densities of the inlet and outlet fluids at the inlet and outlet temperatures

\(z_{\text{c}} \left( t \right)\) = the user-supplied table of the elevation of the thermal center as a function of time

\(z_{\text{in}}\), \(z_{\text{out}}\) = the inlet and outlet elevations

\(g\) = the acceleration of gravity

5.4.5.1. Table HX Input Description

For model independent HX input refer to Section 5.4.2.7.

Table 5.4.9 Input in PMR4IN (Block 18) for the all table look-up IHX models

Variable	Range	Description
TMPMTB	>=0.0	Times for DTMPTB and ZCENTR.
ZCENTR	-	Height of thermal center for an IHX or steam generator.

Table 5.4.10 Input in PMR4IN (Block 18) for a normalized temperature drop table look-up IHX model

Variable	Range	Description
DTMPTB	-	Normalized temperature drop for an IHX or steam generator.

Table 5.4.11 Input in PMR4IN (Block 18) for an outlet temperature table look-up IHX model

Variable	Range	Description
DTMPTB(1,ITAB)	> 1.0	Steady State outlet temperature for the primary element in an IHX or steam generator.
DTMPTB(2:,ITAB)	> 0.0	Outlet temperature for the primary element in an IHX or steam generator.

Table 5.4.12 Input in PMR4IN (Block 18) for a normalized heat rejection table look-up IHX model

Variable	Range	Description
DTMPTB(1,ITAB)	= 1.0	Steady State normalized heat rejection for the primary element in an IHX or steam generator.
DTMPTB(2:,ITAB)	-	Nomalized heat rejection for the primary element in an IHX or steam generator.
DTSIHX	>0.0	The inital temperature difference between the inlet and out of a heat exchanger.
VSIHX1	>0.0	The volume of the inlet region of a heat exchanger.
VSIHX2	>0.0	The volume of the outlet region of a heat exchanger.