Stichting Laka

Event Report Forms (ERFs) are filed to the IAEA. Sometimes there are multiple event reports, updating the rating, the event description. Here you only see the latest event report

ERF send date: Fri, 03-06-2005
ERF description: On August 25th 2004, with train A of the ESW in service, train B of the ESW was started up in order to proceed with the reparation of a check valve and replace a flow meter according to its replacement program. At the impulsion side of train B an immediate drop of pressure was detected after the pump was started up, what led the crew to stop the pump and proceed to investigate the event. After checking it locally, a break was found in hatch neck EF-18-I, located in a small chest after the pumps building.

After reparation and restoring operability of train B, plant personnel proceeded to inspect train A of the ESW. Similar loss of thickness due to corrosion was found at the same hatch neck as the repaired one in train B. Similar reparation was conducted in train A. The remaining hatch necks showed thickness within the engineering margins. Although some of them presented corrosion points, the corrosion process was less advanced than the one found in the small chests located after the pumps building.

Afterwards, it has been revealed that the utility was aware of the degradation of train A almost simultaneously to the degradation of train B since 1993. Routine inspections reports of the system had identified pervasive corrosion and exfoliation in the outer part of the hatch necks closer to the impulsion side, the one that broke in train B and its counterpart in train A. This was due to inadequate protection of the steel surface against the erosive environment inside the small chest. Despite this, maintenance activities had not been improved. In year 2000 no measures were taken after an inspection report had recommended an measure of the thickness of EF-18-I hatch neck. May, the 10th 2004 percolated dampness was identified in EF-18-I and the utility did not declared the correspondent “non-compliance” status of the plant. The utility did not take any measures of thickness, did not check the rest of hatch necks nor related this finding with previous inspection reports that had warned about a process of pervasive corrosion.

ERF rating date: 01-06-2005
ERF contact person: Rodolfo Isasia
ERF address: Nuclear Safety Council
ERF affiliation: INES Coordinator

This map shows a selection of reports from nuclear and radiological incidents stored in the IAEA NEWS-database.
Locations are estimates. Contact us if a location is wrong.
The map shows a maximum of 100 incidents. If hundred incidents or more are within the map, the yellow perimeter indicates from where events are excluded. Drag or zoom the map to explore different areas.

Power Reactor Research Reactor Radwaste Facility Enrichment Facility Radiation Source Irradiation/Accelerator Facility Transportation

Fuel Fabrication Fuel Reprocessing Research Facility Mining/Milling Radioisotope Processing/Handling Facility Other