Beneficiary Organisation Details
Czech State Office for Nuclear Safety
http://www.sujb.cz
Hungarian Atomic Energy Commission
http://www.haea.gov.hu
Project Aims
The ultimate goal of this project was to develop a methodology for qualification, on request of the Beneficiary Countries Safety Authorities, of an integrated Leak Detection System for the primary coolant circuit (LDS) pipelines in relation to the leak before break (LBB) concept being applied in the VVER 440-213 NPP.
According to the Czech Safety Authority request the LDS had to include at least three independent and redundant methods of leak detection. One of these had to be based on acoustic emission, for which problems of leak localization and quantification had to be particularly examined with respect to related work needed for qualification tests. A few other methods had to be considered concerning respectively mass balance, humidity rate or activity measurement.
 
 
Project Results
LDS Qualification was considered to be the ultimate result of the appliance of a Qualification Programme, which usually followed the Qualification Plan.
 
A methodology for development of LDS Qualification Plan was elaborated under the PH4.2.3/93 project and this methodology was applied to draft the particular Qualification Plans for the three independent legs ( sub-systems) of LDS, which used diverse technologies and phenomena for detection of pipe leakages. The three set of equipment used were as follows:
 
 

• Tools available from the activity measurement equipment already installed at Dukovany NPP to diagnose leakage;

• "LMS - 96 system", based on the acoustic emission technique and developed by SKODA;

• "HUMON system", based on the humidity rate measurement technique and developed by VUJE Institute.

   

In the Qualification Plan two major issues were addressed:
 

• validation of the suitability of the LDS, e.g. to demonstrate that the three selected technologies are appropriate and can meet reliability requirements;

• validation of the LDS capability, e.g. to demonstrate that each of the subsystems is able to perform the assigned mission in all the required operating conditions.
   

Some results from Qualification Tests of Leak Monitoring System Skoda type LMS-96 performed at experimental loop in SVUSS Bechovice Institute were also included in the final Ph4.2.3/93 project report. .
 
 
In addition to the Qualification Plan developed for LDS, a guideline was provided which addressed the need to update in future the relevant plant operating procedures in order to provide adequate instructions to the operator for the use and correct interpretation of LDS readings.
 
 
The project report were presented for consideration of the Czech Nuclear Safety Regulatory Authority.
 
 
 
Further Project Results
Further information on the project results could be sought from the beneficiary organisations.