Diagnostics Center
URL: https://diaprom.ru/
Address: office 329, Gazgoldernaya st. 14, Moscow 109518
Telephone/Fax: (495) 690-9195

Reactor mode monitoring system of WWER-1000 reactor system (LPMS)

Experience of Implementation of LPMS Software-Hardware Suite

In 2016 LPMS is in operation at Tianwan NPP (China) Units 1, 2, Kalinin NPP Units 3, 4, Rostov NPP Units 2, 3, Bushehr NPP (Iran) Unit 1, Novovoronezh NPP Unit 6.

LPMS is installed at Kudankulam NPP (India) Units 1, 2.

LPMS has been supplied to Leningrad NPP-2 Unit 1.

Loose parts monitoring system (LPMS) is an off-line diagnostic system connected with other systems of the power unit over the local network.

LPMS is intended for to detect inside the primary circuit of WWER reactors:

  • foreign objects left inside during the scheduled outage;
  • equipment parts that got dismantled in the course of operation;
  • poorly fastened equipment parts.

Using LPMS at NPPs enables:

  • reduction and prevention of primary circuit equipment damage due to early detection of hazardous objects inside the primary circuit;
  • reduction of the time needed for repair in case of loose parts detection inside the primary circuit because the defect has been localized.

Loose parts are detected on the basis of acoustic noise bursts that are the result of shocks loose parts produce in the coolant flow against the inner surface of the primary circuit equipment and pipelines.

LPMS basic specifications are:

  • around-the-clock operation;
  • acoustic noise monitoring is focused on physical trap zones of loose parts and zones that are likely to catch poorly fastened parts;
  • in case a burst of acoustic noise (event) is detected the system records complex data that characterize the shock parameters, the system hardware and reactor system condition (values of process parameters from the upper level systems);
  • system software and hardware enable continuous monitoring of LPMS operability in any power unit operating modes both in the automatic mode and in the user-initiated mode;
  • capability of automatic rapid processing of acoustic noise input signals and postponed data processing by LPMS operator in the interactive mode to make the diagnostic results more precise;
  • event classification based on the similarity principle applied to the events previously identified by way of postponed analysis.

LPMS enables transmission of generalized data about the recorded events into the upper level systems (to be displayed in main control room in particular), of diagnostic data into the unit integrated diagnostic system (if any) and into the industry diagnostic system of JSC Concern “Rosenergoatom” (subject to the availability of communication links).

The tasks set are accomplished by LPMS software-hardware suite that includes in the standard design:

  • Sensors with integrated cable and attachment nodes - 20 pcs.;
  • preamplifiers - 20 pcs.;
  • junction boxes - 4 pcs.;
  • data measuring unit - 1 cabinet;
  • Test shock device consisting of 4 pulse hammers and power supply station;
  • SPTA;
  • Set of assembly tools and accessories;
  • Operating documents package;
  • Software package including system and application software.

LPMS can be equipped with additional sensors and event monitoring modules to increase the number of measuring channels.

Sensors are installed on the surface of the primary circuit components in such a way so as to enable the monitoring of acoustic noise level along the whole circuit. But the main focus is on physical trap zones of loose parts and zones that are likely to catch poorly fastened parts.

The sensor signals are mostly processed in the data measuring unit that includes analogue processing units and industrial PC for digitization, processing and analysis of data recorded by the system if a noise anomaly occurs.

A burst of acoustic noise on the surface of the primary circuit equipment and pipelines is recorded as an event that is identified by the system as interference (spurious event) or a real noise anomaly in the course of automatic processing. The identification is based on the database of event classes created as a result of the system operation at an NPP unit.

Certain measures are envisaged to confirm the system software and hardware operability. They are implemented by way of:

  • Loose parts shocks simulation produced by pulse hammers;
  • Measurements of background noise;
  • Sending a test signal generated by the system to the preamplifier input;
  • System hardware periodic status scanning.

Each monitoring facility enables independent operability check of any LPMS components.

The system is supplied with a package of operating documents including:

  • Operating instruction;
  • Components connection diagram;
  • Assembly documents;
  • Operating manuals for system components;
  • Documentation for the application software.

The documentation provides NPP personnel with all the data needed for LPMS operation and maintenance.

LPMS commissioning at NPP is phased. LPMS is supplied to NPP with pre-settings based on the previous operating experience. During pilot operation the system is tailored according to the needs of a certain power-generating unit. The pilot operation usually lasts a year.

LPMS Operation AlgorithmLPMS Operation Algorithm
Data-Measuring Unit LPMS UIIData-Measuring Unit LPMS UII
Power Supply Station SP-4MМPower Supply Station SP-4M