INES Levels

INES 1: Anomaly

Impact on Defence-in-Depth
  • Overexposure of a member of the public in excess of statutory ­annual limits.
  • Minor problems with safety components with significant defence-in-depth remaining.
  • Low activity lost or stolen radioactive source, device or transport package.
(Arrangements for reporting minor events to the public differ from country to country. Also, it is difficult to ensure precise consistency in rating events between INES Level-1 and Below scale/Level-0)
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Spillage of uranium-bearing effluents into the environment at the SOCATRI nuclear facility

During the night of July 7 to 8 2008, an incident occurred at the site of the SOCATRI company. A tank of the Uranium-bearing Effluent Treatment Station (STEU) of the SOCATRI facility overflowed in its retention tank. This retention tank was not leakproof at that time and caused a pollution of the environment.

On July 10 2008, four ASN inspectors, accompanied by two IRSN experts, carried out an in-depth inspection of the STEU facility. They examined the premises, the events chronology and the first corrective actions implemented by the licensee.

Category: Other France Tricastin »


Deterioration of the containment depression of unit 1 during an air locking operation for maintenance activities

During the morning shift on 07/07/2008, two workers, involved in the maintenance of safety valves, were instructed to repair a leakage at a safety valve in the cooling water system of the recirculation fans used for cooling the containment air space of Unit 1. The entry to the room is possible through an air-lock. The air-locking operations were carried out by the two workers, having entrance permit to the area, by disregarding the relevant regulations.

Category: Power Reactor Hungary Paks »


Loss of Industrial Gamma Radiography Exposure Device containing Ir-192 radiography source

On April 7, 2008, a licensee in Chiba prefecture notified the Ministry of Education, Culture, Sports, Science and Technology (MEXT) that one of their industrial gamma radiography exposure devices containing a sealed source of 370 GBq of iridium-192 was lost.

Category: Radiation Source Japan »


Fast stop of the main circulation pumps and simultaneous loss of their fly wheel systems during reactor scram.

There was a reactor scram and trip of main circulating pumps during start -up after the annual outage at Olkiluoto unit 1 on Friday, 30 May 2008 at 6:31 am. The power of the unit 2 was also reduced later in the Friday evening to ensure adequate core cooling in potential transients with similar sequence of events.

The event did not cause any on-site or off-site radiation consequences. The event was classified as level 1 on the INES scale.

Category: Power Reactor Finland Olkiluoto »


Stainless steel coils contaminated by Cobalt 60

In the period between January and February 2008 the Environmental Care Command (Comando Carabinieri per la Tutela dell’Ambiente - CCTA) impounded at some Italian firms about 30 tons of stainless steel contaminated by Cobalt 60. The material, in the form of rolled steel coils (6.0 mm thick, 2 m width, about 10tons mean weight), had been imported to Italy from China in May 2007, arrived at the La Spezia port together with some other not contaminated coils. The rolled steel coils were manufactured in China. The contaminated coil identification numbers are: KA70168101, KA70168102, KA70168103.

Category: Other Italy »


Cs-137 source found in a scrap container prepared for export

On April 19, 2007 the on field surveyors from the Lebanese Atomic Energy Commission (LAEC) were performing their routine surveillance of the scrap containers prepared for export on Tripoli Port. Using handheld survey equipment (Exploranium GR-110), they measured a reading equivalent to 220 nanoSv/hr on a 20 ft container (background is around 70 nanoSv/hr). They unloaded the container and upon tracing the source of radiation they found a lead sphere-like object which was expected to be a source shield, within it a cesium-137 source was found.

Category: Other Lebanon »


Incidental Exposure during maintenance tasks

On December 7th, 2006 the radiation safety officer of a licensed facility notified the Nuclear Regulatory Authority about the incidental exposure of twenty-six workers that were carrying out maintenance tasks and inspection inside coke cameras, commonly used in the process of petroleum refineries .
These workers were exposed to neutron radiation of nuclear gauges containing approximately 37 GBq of Am-241 (Be), located in those cameras.

Category: Radiation Source Argentina »


Reactor Scram due to Inadvertent Opening of Multiple SRV’s

On March 6, 2007, Leibstadt NPP (GE BWR/6, 1165 MWel, net) was operating at the full rated power. Plant staff was preparing planned instrumentation functional tests at the SEHR division 51, which required the simulation of SEHR actuation signals. The SEHR-system (Special Emergency Heat Removal System) is a bunkered, protected system designed to ensure the safe shutdown and residual heat removal during special emergency conditions, e.g. airplane crash, explosion, fire, third party action, etc.

Category: Power Reactor Leibstad Switzerland »


Radioactive source (Cs-137) found at a scrap yard

On February 12th 2007 the Inspectorate was notified by a metalscrap dealer that they had a radiation alarm of their portal detector. Using handheld survey equipment an enhanced radiation level at the surface of a 20 ft container of 5 milliSieverts per hour could be determined. The container was unloaded by a firm specialised in tracing and recovering radioactive sources in scrap. The container was completely filled with pressed packages of stainless steel scrap, with dimensions of approximatley 85 x 40 x 15 centimeters.

Category: Radiation Source Netherlands »


Theft of Nucleonic Density Gauge Device containing Cs-137 source

An industrial ionizing radiation gauging device (IRGD/nucleonic density gauge) containing about 9.25 GBq Cs-137 source, used in a Coal Washery, was stolen on 16 November 2006. The overall weight of this IRGD is about 45 kg with lead shielding.

Category: Radiation Source India »