Ground water secondary circuit analyzer of a Nuclear plant

Plant description

Chemical analysis plant of secondary circuit water of a nuclear plant. The secondary circuit of the type PWR nuclear power plants (powerwater reactors) is used to condense the steam from the primary circuit, coming from the nuclear reactor, which is used to rotate the steam turbine. The water of the secondary circuit must have certain conditions in order to optimize the process and make the cooling water does not condense primary below a certain temperature.

The chemistry department is responsible for ensuring these optimal conditions and therefore need to know the different values.

Using these data and its analysis can correct any deviations by the contribution of different chemical compounds.

Description of the automation system

This installation has been automated with a distributed control system SIEMENS PCS7 v6.1. It is based on a dual architecture; the first Ethernet network connects different PLC’s (AS) with Server (OS). The second connects these servers (OS) with different clients (OT).

Supervision (OT)

Supervision includes two operation stations (OT) with touchs-creen and operatives from the analyzers room, one for each of the two groups, and a third desktop station to the spervisors office of chemical laboratory.

Control (AS)

For the control has been installed an AS of the type SIEMENS S7-400, for each group, with central peripheral which receive analyzer signals in a traditional way, via 4-20 mA and 0-10 V, and 43 analyzers for each group arriving via Profibus-DP, for this reason, two separate networks in each AS of 1.5 Mbps have been created.

Different AS communicate their data to redundant servers using the control Ethernet network (with ISO protocol).

We have also communicated data analyzers via RS-232 MODBUS with another external monitoring system that allows having different data to the corporate network Anavar.

Engineering station

The engineering station is located in the control room of te chemical laboratory. It has doble ethernet connection in order to access to the operation stations and servers (supervision network) and to the PLC’s (control network).

The AS programing is performed through CFC (oriented objects programming).

Servers (OS)

There are two servers, one redundant of the other, to prevent the failure of one system. Both also have dual ethernet connection to access the PLC (via ISO protocol) and collect data, and then send them to the operation stations (OT’s) via TCP / IP.