RELAP5 Interactive Controls

This appendix uses the Oconee-1 input deck as an example to show how to edit the deck to simulate hardware failure and human actions on a component for the use of ADS. The operation of Main Steam Isolation Valve (MSIV) is used to exaplain the editing process.

1. The MSIV for this example is component 821 shown in the input deck. Search keyword “8210000” within the input deck to find the description of component 821. Found the description of Component 821 as the following

8210000 astmvlv valve * steam gen a main steam vlv

8210101 350010000 820000000 1.6872 0.0 0.0 0100

8210201 0 134.49423 134.54580 0.0 * 1560.8944

8210300 srvvlv

8210301 872

1. Card “8210300” indicates that the valve is modeled as a servo valve (i.e., controlled by air pressure). The open of a servo valve can be adjusted between 0 (i.e., fully close) and 1 (i.e., fully open) indicated by the value of the control variable (i.e., 872) in the card “8210301”.
2. Search “2050872” for control varoiable “872” based on the format “205CCCC”.

20508720 msiva mult 1.0 1.0 0

20508721 msa 1000000000

20508722 cntrlvar 3199

20508723 cntrlvar 871

For the card 20508723, the key word “cntrlvar” indicates that 871 is a control variable (see A15 control system of [The Thermal Hydraulic Group, 1999 #1225] for detail). Thus, search “2050871” in the input deck show:

20508710 msaisol tripunit 1.0 1.0 0

20508711 -1760

The above shows that the control variable 871 is a function of trip 1760. The format for a trip card in the deck is “206CCCC”. Seacrh “2061760” in the deck found the relevant cards include:

20616500 561 or 420 n * rcpb2 manual trip

20616510 1647 or -552 n * rcpa1 trip

20616520 1648 or -553 n * rcpa2 trip

20616530 1649 or -554 n * rcpb1 trip

20616540 1650 or -555 n * rcpb2 trip

20616550 1651 and 1652 n * loop "a" loss of flow

20616560 1653 and 1654 n * loop "b" loss of flow

20616570 1655 or 1656 n * rcp scram

20617580 486 or 1753 n * low cond vac or mfp trip

20617590 1758 or 1770 l * rx trip

20617600 1759 or 439 l * manual trip

20617620 577 or 1657 n * manual or rcp trip

20617630 1762 or 452 l * hi power

20617640 1763 or 454 l * hi pressure

20617650 1764 or 456 l * lo pressure

20617660 1765 or 458 l * hi temperature

20617670 1766 or 460 l * pwr/flow mismatch

20617680 1767 or 461 l * f(p,t) > p prim

20617690 1768 or 1760 l * turbine trip

20617700 1769 and -578 n * scram actuator/override

20604390 tbtrip 1000000000 gt null 0 0.0 l * manual trip turbine

The high level logics of control varable 871 is shown in Figure F.1. It show that either reactor trip (i.e., represented by trip 1759) or turbine trip (i.e., represented by trip 439) would trip card 1760. In another word, either reactor trip or turbine trip would change the trip 1760’s state to TRUE. This results in the value of control variable 871 to become zero base the logic shown for the card “20508710”:

• • If 1760 is TRUE then the value of 2050871 is zero (0.0)
    • If 1760 is FALSE then the value of 2050871 is one (1.0)

Figure F.1 The logic for calculating control variable 871.

For the card 2053199, its value is a function of two tables as shown in the card “2053199” which represnts the automatic control of MSIV open degree after RCPs or MFPs trip.

20531990 "minuld " stdfnctn 1.0000000 1.0000000 0

20531991 min cntrlvar 3197 cntrlvar 3198

* calculate rcp trip uld runback from table 002

20531970 "rcprunbk" function 1.0000000 1.0000000 0

20531971 time 0 002

* calculate mfp trip uld runback from table 003

20531980 "mfprunbk" function 1.0000000 1.0000000 0

20531981 time 0 003

For the card 20508721 whose values is the value input for the interactive control “msa”. Search keyword “msa” within the input deck and found:

828 msa 1.0

20605820 msa 1000000000 gt null 0 0.0 n * main steam "a" opener

20605830 msa 1000000000 lt null 0 0.0 n * main steam "a" closer

Only the first of the above three lines is what we ware interesting. The card “828” indicates that the msa initial value is 1.0. This card can be used to close the MSIV due to the operators’ interactive actions or hardware failure.

1. Modify the MSIV (i.e., component 821) logic for fail to close after reactor trip. Figure F.2 shows a high level logics for calculating the control variable 872. It inidicates that card 2050871 determines the close/open of the MSIV. Card 2053199 determins the degree of open of the MSIV. IC 828 is a overwrite card for human action to close the MSIV. As a result, the logic from the card 2050871 is the one need to be revised.

Figure F.2 A high level logics for calculating control variable 872.

1. The planned change is to add a interactive control card (IC_867) and a control variable card (i.e., 2052800). Add the following lines into the input deck:

867 msivfc 0.0

20528000 msaisoc sum 1.0 1.0 0

20528001 0.0 1.0 cntrlvar 871

20528002 1.0 msivfc 1000000000

The card 867 would be usede by the hardware reliability model of ADS to model MSIV fail to close after reactor or turbine trip. Card 205280000 is used to incorporate the logic change to calculate the value of “2050872” which ultimately determines the MSIV state.

1. Change the logic of calculating “2050872” to

20508721 msa 1000000000

20508722 cntrlvar 3199

*20508723 cntrlvar 871

20508723 cntrlvar 2800

Note that a star in front of a line in the input deck indicates that it is a comment. The new control logic for 2050872 becomes as the one shown in Figure F.3.

Figure F.3 The revised logic for MSIV A failure. The failure of MSIV fail-to-close can be induced by change the IC_867 from 0.0 (i.e., the initial value) to 1.0 after reactor or turbine trips.

1. In the ADS GUI, add the follow interactive control into the System Module (as sgown in Figure F4). This would result in the following line been added into the RELAP%_channels.txt

IC_867 867

Figure F.4 add an interactive control

1. Add the corresponding control in the Plant Indicators/Controls of the ADS GUI as shown in Figure F5. This would result in the following line been added into the ControlPanel.txt.

X_MSIVFC IC_867 20.0 1.0 0.0 0.0 1.0

Figure F5 Add a control into the control panle module

1. Add a component “MSIVA_F” as the component that triggers the hardware failure mechanism. This would result in the following line being added into the ControlPanel.txt (See Figure F6).

MSIVA_F LT_1770 Trip_Time 20.0 OPEN SMALLER_THEN_OPEN 1.0E-5

Figure F6 adding a component to activate the MSIV_A failure mechanism

1. Add a MSIV_A fail to close event into the hardware reliability module of the ADS with use of the ADS GUI (as shown in Figure F7). This would result in the following being added into the SystemReliability.txt.

MSIVA_F X_MSIVFC 1.0 0.01

Figure F7 add a MSIV_A fail-to-close in the hardware reliability module

1. Save the ADS project from the ADS GUI. The new edited Oconee input deck with the above revision is named indeck2.i.