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: Wed, 07-09-1994
ERF description: On August 22 when Ringhals 4 was operating at 51% with one turbine, the power supply to 400 kV grid was interrupted for 9 minutes. The transition to house load operation failed and Ringhals 4 scrammed. At the scram a control rod did not reach the bottom but jammed 18 steps from a wholly inserted position. (The whole insert in the position is 228 step).
At the subsequently performed drop test the same rod jammed 24 steps from a wholly inserted position. The drop tests also revealed that another 3 control rods jammed between 6 and 12 steps out (the total number of control rods is 48). All 4 rods are placed in fuel assemblies which were placed into the core 1991.
Investigation about the cause of the jammed control rods in the guide tubes proceed.
Table II, Severity classification criteria for degradation of defence in depth with an initiator.
Safety function availability: full, initiator frequency: high/expected, INES scale 0.
ERF rating date: 06-09-1994
ERF contact person: MR. F. REISCH
ERF address: Sweden
ERF affiliation: SWEDISH NUCLEAR POWER INSPECTORATE (SKI)

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