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Inspection activity

Inspection activity of UJD at NPP Mochovce focused on inspection of activities during commissioning and operation, on meeting limits and conditions of safe operation, observance of operational procedures by operating personnel and on performing periodic tests of equipment according to programs prepared for periodical verifications and inspections during operation.
In 1999 the inspections on Unit 1 focused on:

Beyond the scope of inspection plan, a lot of special inspections were performed on Unit 1, focusing on:

Routine inspections on Unit 1 focused on observing regime at the unit control room, using valid documentation, observing limits and conditions, as well as observing operational regulations and procedures. Findings of routine inspections (there were 46 inspections in 1999 on Unit 1 of NPP Mochovce) , most often as incompatibility between operational procedures and the as-built status of the equipment after implementation of safety measures, were entered into the log-book of regulatory supervision as imposed measures to remove the shortcomings which were found. Inspection activity on Unit 2 of NPP Mochovce focused on unit commissioning.
During the non-active tests it concentrated mainly on control of consistency in performing activities at NPP Mochovce according to the valid programs for the relevant commissioning phase. The same emphasis was placed by UJD on acceptability criteria for testing equipment and systems during phase 1 and 2 of extended hydro-test. UJD inspectors by their physical presence at the tests, which were selected from the relevant programs, checked the approach of the testing personnel to fulfill the test programs and acceptability of results (e. g. testing of tightness and strength of hermetic parts, pressure and tightness tests of the primary and secondary circuit, tests of emergency feed water supply system, tests of the cooling system in seismic conditions, complex verification of automatic reactor protection system, total loss of house load, etc.). Inspectors focused mainly on deviations found, compared with the features determined by the design, or approved program of tests, for identification of causes, their removal, repeated tests and achieving acceptable results.
The inspection results show that partial shortcomings found during inspections of non-active tests were immediately removed, or those which had no effect on the following activities according to the valid program of testing, were recorded into the "list of uncompleted works and shortcomings ", removal of which was assured continuously and which was updated by those cases which had been already removed and complemented with the new ones.
Special attention of inspectors was paid to realization of safety measures focused on improving the nuclear safety standard of the unit. It can be stated that implementation of safety measures on this unit (compared to Unit 1) before commissioning was more consistent (level of their implementation on Unit 2 of NPP Mochovce before physical start up was the same as on Unit 1 of NPP Mochovce after the shut-down for refueling, during which design and on contract basis prepared safety measures required by UJD were realized).
Based on results of a team inspection concentrating on checking the readiness of Unit 2 for commissioning, UJD issued a Decision-Making Act to start the phase I of physical start up of the reactor, i. e. with loading the fuel. During the active test phase inspectors of UJD checked the readiness of equipment for launching individual phases of active start up, compliance of tests performed with approved programs, compliance with the programs of quality assurance during performed tests, (e. g. initial and final test conditions, fulfilling criteria of success, activity of the personnel, etc.) and control of fulfilling the planned program of tests within individual phases of commissioning.
Inspection activity of UJD on Unit 2 of NPP Mochovce concentrated also on inspection of nuclear materials, inspection of physical protection, checking preparation of the operating personnel and on control of emergency preparedness.
UJD organized a team inspection to check readiness for launching the second phase of physical start up, i. e. by UJD Decision-making Act an approval was given to achieve the first minimum controlled power increasing of the reactor and also a team inspection checked the readiness for launching the power escalation phase. After tests performed in 1999 on physical levels of power as well as on levels up to 35 % , no shortcomings were found which would be in contradiction with the design or the approved POSAR. Some shortcomings in the design found during commissioning of Unit 1 were removed on Unit 2 still before starting commissioning, which is recorded in the documentation on evaluation of tests. In a form of routine inspections (80 in 1999) on Unit 2 of NPP Mochovce compliance with the quality in realization of commissioning programs was checked continuously, the status of unit equipment and its compliance with the protocols on readiness in different phases of commissioning and cleanness in Unit 2. Also the activity of personnel during tests, as well as during normal operation was checked according to the operational procedures or operational instructions.
On the basis of the knowledge acquired by UJD through inspections during Unit 2 commissioning it is necessary to state that shortcomings occurred mainly in technical documentation, where the changes resulting from realized safety measures were not incorporated sufficiently flexibly into it and there were also problems with keeping Unit 2 rooms clean.
With regard to the shift staff, there were no significant shortcomings found. Personnel of Unit 2 of NPP Mochovce have sufficient experience, which was partly gained during commissioning of Unit 1. Based on evaluation of operational events, results of inspection activity, but also taking into account operational indicators,
UJD evaluated operation of Unit 1 of NPP Mochovce in 1999 as safe and reliable.
Results of inspections and tests on Unit 2 NPP Mochovce during commissioning until achieving the output level of 35%show that the unit is, with respect to equipment and systems as well as with respect to the activity of personnel, well prepared for the next phase of commissioning, which has been performed in 2000.

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© Nuclear Regulatory Authority of the Slovak Republic, 2000