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Automatic control of primary circuit piping welds at South Ukraine NPP (SU NPP)

Automatic control of primary circuit piping welds at South Ukraine NPP (SU NPP)


1) Background
The scope of this project was defined as a continuation of some tasks implemented under the OSA to SU NPP of Tacis 92 program. During the previous, initial phase the following activities had been developed:
•Stress analyses of primary circuit to establish the design conditions and feasibility of application of western standards.
•After above stress analyses an inspection program proposal was elaborated according to ASME criteria as well as data base and computer support.
•Feasibility of application of the inspection program; Possible interferences and difficulties to carry out the program by using automatic inspection system were studied "situ" and its feasibility confirmed.
•Specification of the inspection system. The specification of the inspection system was performed as the reference for its supplying to SU NPP.
•Specification of calibration blocks. A specification of blocks was issued for the fabrication of one calibration block and three specimens with artificial flaws. These blocks were supplied to the NPP and used for personnel training and validation of the procedures.
The objectives of the present project were the following:
•providing an evaluation tool for detected flaws, whose size exceed the acceptance limits established according to fracture mechanical analyses
•updating of ultrasonic inspection procedures for the primary circuit piping welds
•technical support to SU NPP for validation and licensing of the ultrasonic inspection system and the updated procedures
•additional training of the personnel involved in the ultrasonic inspection
•technical support at the beginning of the application of the procedures during the first in-service inspection .

3)Project Results – Achievements (With reference to the TORs)
As a first achievement an indication assessment manual was developed. By means of the manual, immediate decisions regarding acceptability of detected defects could be taken. Such decisions may be taken by using simple graphs known as decision maps and also by specific software. Both instruments are included in the manual.?
Inspection procedures based on the ASME code, Section XI were provided. The old Ukrainian procedures used before were adapted to the ASME approach. The procedures were verified and validated by using special calibration blocks with implanted mechanical fatigue cracks according to modern practice (ENIQ etc.).
The new inspection procedures had to be validated by the Ukrainian regulatory authorities. The licensing basically consisted of establishing operation conditions and characteristics of the inspection system and to verify that it was acceptable according to Ukrainian standards in force at those days as well as with requirements of the NPP utility and final end users. Technatom’s contribution in the licensing procedure was mainly related to:
•training of personnel; 4 selected persons were trained and qualified
•qualification and certification to carry out ultrasonic inspections by using the supplied system
•provision of calibration blocks with fatigue cracks
•documentation and checking of systems
Finally the consultant provided technical assistance in real ISI (In Service Inspection) conditions of the primary circuit welds at the SU NPP. The ultrasonic inspection system provided and used in these inspections was performing well and as a result of the ISI several indications could be detected, some of them with responses higher than the recording level. These indications were evaluated and compared to records from previous manual ISIs. As a result the indications were considered acceptable and no evolution of the defects could be observed.
4)Comments (Quality of the results, Lesson learnt, Recommendations for follow-up)
The project was considered very successful and excellent results were achieved, which will be of great benefit for the utility in future ISI. The most important results were the following:
•The supplied mechanized ultrasonic inspection system provides possibility of permanent reliable data recording of ISI
•Possibility of reliable repeated checking on selected areas
•Decreasing of the influence of human factor in the inspection results
Further Information
Further information on the project results could be sought from the beneficiary organizations.
The Project Final report is available at the JRC-IE archive.

General Information

Automatic control of primary circuit piping welds at South Ukraine NPP (SU NPP)
€ 386.076,00
Budget year: 
Types of activities: 
Equipment Supply
South Ukraine
Duration (months): 
Contracting authority: 
Special Fund (EC)
Partner (Beneficiary): 
Old reference: 
CA 94-0046 & 94-1165 (PA)
Project reference: 
Decision number: 
multi annual
Method of procurement: 
Special Fund (Procurement Agent)
Procurement Agent contract: 
Crown Agents 94-0046&94-1165
Procurement Agent reference: 
Signature date: 
Effective contract date: