Objectives

In line with the funding of TACIS 94/95 programme, equipment for detecting local leaks, based on

physical principles (noise or humidity measurements, or others) should be installed at Smolensk NPP.

The project is to provide equipment for the detection of local leaks on an RBMK 1000 primary circuit. It

is an application of the methodology financed under Tacis 94 and 95. It covers the installation of a pilot

leak-before-break instrumentation system in a single sealed compartment on Unit 3 containing reactor

coolant pipework. The equipment will assist in early leak detection, and preventing emergency situations caused by pipework rupture.

Project Description

Scope of the project

The scope of work includes the design, licensing, manufacture, testing, obtaining certification of the leak-before-break detection equipment by Gosstandart, delivery, supervision of installation and commissioning at site, acceptance testing, design documentation, operating and maintenance instructions, training of personnel, supply of spare parts, warranty repairs, specialised tools and equipment and responsibility for failures during the guarantee period.

The integrated leak detection system is required to initiate warning and alarm signals in the main control room in the event of detection of a leak exceeding an allowable flow rate. No currently (1995) available single leak detection technique is capable of providing optimum performance in terms of sensitivity of detection, and accuracy of quantification and location.

The system should monitor the cooling circuit equipment. Three complementary techniques should be

used. These techniques are using diverse physical principles and operate independently of one another. The leak detection system to be installed presents a local automated complex, requiring no

operator interference, and provide continuous monitoring data, current values of the variables, and

adjustment of alarm and warning thresholds. The equipment is to operate on a continuous 24-hour duty cycle during the unit operation between preventative maintenance periods. The primary circuit leak detection system includes the following functions:

•  Acquisition, processing, analysis of sensors signals at each measuring channel;

• Comparison of measured and calculated values to specified/prescribed limit;

• Data storage and archiving of current and predecessor parameter values of each measuring

• channel;

• Registered signal amendments trend determination;

• Alarm and attention audio and light signalization of parameters alterations controlled;

• Emergencies archive formation;

• Coolant leakage evaluation;

• Coolant leakage location detection;

• Component parts and items self-diagnosis.

Implementation of the project

The project, which worth 1 908 000 €, was contracted to Framatome and implemented successfully during the period 04 Aug 2004 - 04 Aug 2006.