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, 23-02-2018
ERF description: On August 02, 2017, plant was in shutdown state when bonnet gasket of moderator drain tank outlet valve was replaced as per preventive maintenance program. After the maintenance work, moderator drain tank was slowly filled with heavy water on August 04, 2017 while its outlet valve was kept close as per procedure. After about 2 hours of moderator drain tank filling, drop-wise leak of heavy water started from its outlet valve bonnet gasket that gradually kept on increasing. To save heavy water from leaking, tank outlet valve was manually opened and heavy water was transferred to dump space. Boiler room was on purging with fresh air before this leak to carry out maintenance jobs. Purging was terminated and spilled heavy water was collected.
In response to the requirement of the regulatory body, K-1 performed Root Cause Analysis (RCA) of this event and submitted the report on October 02, 2017. According to this report, about 1589 kg spilled heavy water of moderator system was collected from reactor building floor. Among the workers involved in valve isolation and heavy water collection, four individuals exceeded the annual regulatory dose limit of 20 mSv/year. The doses received by the overexposed workers were 20.8 mSv, 24.2 mSv, 30.9 mSv and 36.2 mSv respectively.
The investigation reveals that the causes of bonnet gasket failure of moderator drain tank outlet valve are less than adequate procedure adherence and absence of supervision during work. The overexposure of four workers resulted due to inadequate preparedness for collection of spilled heavy water. Protective clothing of the personnel involved in leak isolation became wet with heavy water that eventually gave exposure in excess of annual regulatory limit.
ERF rating date: 23-02-2018
ERF contact person: Muhammad Usman
ERF address: Reported by Pakistan Nuclear Regulatory Authority (PNRA) of Pakistan on 23 Feb 2018. Last update on 23 Feb 2018
ERF affiliation: Pakistan Nuclear Regulatory Authority (PNRA)

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