Notifications of events from 1 January 2015 to date

Under the Nuclear Energy Act, licensed operators of nuclear facilities are obliged to promptly report 'events' to the ANVS. This page contains the events that occurred in 2015 (so far).

10 December 2015: NRG/HFR – Activation of underpressure alarm in the Hot Cell Laboratories (HCL) resulting in temporary evacuation of the HCL – INES level 0

On 21 December 2015 the NRG notified the NSRPA (Nuclear Safety and Radiation Protection Authority) that the activation of an underpressure alarm in the Hot Cell Laboratories (HCL) on 10 December 2015 had resulted in the temporary evacuation of the HCL. The hot cells are kept at a pressure below the ambient pressure in order to prevent the possible escape of radioactive materials from the hot cells. When material was being transferred to a transport container the gate to which the container was connected was not properly closed, enabling air from the transport hall to enter the cell, which reduced the underpressure. On hearing the underpressure alarm the operator closed the gate immediately and the HCL was evacuated. Following the evacuation workers entered the HCL with breathing protection and carried out contamination measurements, which showed that neither the gate nor its immediate environment had been contaminated.

The NRG is investigating how this incident could have happened and is to take measures to prevent repetition.

The NSRPA is overseeing the investigation and will assess the results and the proposed measures. Based on the information available so far the NSRPA has provisionally rated this event as INES level 0 (no safety significance), as adequate safety barriers remained in place. A final rating will be assigned once the results of the NRG investigation are known.

29 October 2015: NRG/HFR – Failure of part of the external power supply at the Petten Research Facility – INES level 0

On 29 October 2015 the NRG reported that a regional power failure had temporarily cut off power from the grid to the northern part of the Petten Research Facility on the evening of 28 October 2015. Of the NRG facilities at the Facility only the High Flux Reactor (HFR) was affected.

The emergency power supply systems (diesel generators) came into operation automatically and no safety or security systems were out of action. There was no need to shut down the reactor as it was not operational at the time.

When the power failure occurred the NRG decided to put the Facility’s internal emergency response plan into effect. The emergency response organization met but did not need to take any action. Although the cause of the power failure lay beyond the NRG’s control, the NRG was required to report this event because it is under an obligation to report any event where the Facility’s internal emergency response plan is put into effect.

The NSRPA has rated this event as INES level 0 (no safety significance), as the emergency power supply systems functioned correctly and the emergency organization came into action. Nuclear safety was not at stake.

24 October 2015: NRG/HFR – Malfunction in the secondary cooling water radioactivity monitoring system – INES level 0

On 24 October 2015 the NRG reported that while maintenance work was being carried out earlier that day there had been no monitoring of the radioactivity of the secondary cooling water of the High Flux Reactor (HFR) in Petten for a few hours. Secondary cooling water is the water that is pumped from the North Holland Canal to cool the reactor’s cooling water by means of a heat exchanger. After passing through the heat exchanger the secondary cooling water is discharged into the North Sea. The secondary cooling water does not come into direct contact with the reactor or the primary cooling water and is therefore not radioactive. The radioactivity of the secondary cooling water is monitored in order to rule out the possibility of contamination, for example due to leakage from the heat exchanger.

As soon as it was discovered that the monitoring system was out of action it was restarted and the NSRPA was informed. The NRG has investigated the cause of this anomaly and has taken measures to prevent repetition. It transpires that the monitoring equipment had been switched off incorrectly. Following the malfunction working instructions have been written so that maintenance work of this kind can be carried out error-free in future.

The NSRPA has scrutinized the investigation and found it to be in order. The NSRPA has rated this incident as INES level 0 (no safety significance), as the malfunction was noticed and remedied quickly and it was subsequently ascertained that no leakage or contamination had taken place while the monitoring system was out of action.

15 October 2015: NRG/Other systems – Contamination of a worker and workstation due to leakage from a waste container – INES level 0 (provisional rating)

On 15 October 2015 the NRG reported that it had been discovered on 2 October 2015 that contamination had occurred while transferring radioactive waste containers from one building to another. One of the containers was found to be leaking. As a result of the leakage radioactive material fell on the ground at a few places in one building, and one worker’s hand and shoe were contaminated.

The local emergency response organization was called in and the area was cordoned off. Once the worker had been cleaned of contamination the NRG carried out measurements to detect any contaminations on the site and in the building and removed those found.

The NRG is investigating how this incident could have happened and is to take measures to prevent repetition.

The NSRPA is overseeing the investigation and will decide whether the notification was made in time and the severity of the incident gauged correctly. It will also assess the results of the investigation and the proposed measures.

Given the limited nature of the contamination the NSRPA has provisionally rated this incident as INES level 0 (no safety significance). A final rating will be assigned once the results of the NRG investigation are known.

6 October 2015: NRG/Other systems – Interim storage tanks not emptied at the appropriate time owing to a line that was not properly closed – INES level 0 (provisional rating)

On 6 October 2015 the NRG reported that an anomaly had been discovered in the production process at the Molybdenum Production Facility (MPF) on 21 September 2015. An investigation showed that this anomaly was due to not emptying two temporary storage tanks for radioactive waste from the molybdenum production process at the appropriate time.

The NRG is investigating how this incident could have happened and is to take measures to prevent repetition.

The NSRPA is overseeing the investigation and will decide whether the notification was made in time and the severity of the incident gauged correctly. It will also assess the results of the investigation and the proposed measures.

Based on the information available so far the NSRPA has provisionally rated this event as INES level 0 (no safety significance), as although this constituted a departure from normal practice it has not as yet had any safety consequences. A final rating will be assigned once the results of the NRG investigation are known.

28 September 2015: NRG/Other systems – Evacuation of MPF as a result of an underpressure alarm – INES level 0 (provisional rating)

On 28 September 2015 the NRG reported that the Molybdenum Production Facility (MPF) had been temporarily evacuated as a result of an alarm on 14 September 2015.

The alarm indicated that the permanent underpressure required had fallen off in one of the MPF production cells. The underpressure prevents radioactive materials from entering areas where workers are present or escaping into the outside air. Evacuation of the MPF is a mandatory procedure in situations of this kind.

The evacuation was lifted once the NRG had ascertained that working conditions for the workers were safe again. The NRG did not detect any contamination or emission into the outside air, hence there was no danger to workers or the environment.

The NRG is carrying out an investigation into the cause of the fall-off in underpressure.

The NSRPA is overseeing the investigation and will decide whether the notification was made in time and the severity of the incident gauged correctly. In due course it will also assess the results of the investigation and the proposed measures.

Based on the information available so far the NSRPA has provisionally rated this event as INES level 0 (no safety significance), as adequate safety barriers remained in place. A final rating will be assigned once the results of the NRG investigation are known.

16 September 2015: NRG/HFR – Control rod anomaly – INES level unrated as yet

On 16 September 2015 the NRG reported that the High Flux Reactor (HFR) had been shut down as a precaution, as the NRG had observed an increase in ‘noise’ in devices that monitor the reactivity in the reactor. The readings were fluctuating more widely than would be expected during normal operation, which could be indicative of an anomaly in operation or a fault in the equipment. Continuous monitoring of reactivity in the reactor is one of the measures taken to guarantee safety.

The safety margins for monitoring signals of this kind are wide, and nuclear safety was not at stake. The NRG is carrying out an investigation to ascertain the cause. The initial results of the investigation show that there was an anomaly in one of the six control rods that control ‘power’ in the reactor. A malfunction occurred in 2013 that also involved an anomaly in the control rods (see the 26 November 2013 notification on this website).

The NRG took measures at the time to prevent anomalies of this kind. All the control rods, including the one that currently displays an anomaly, were inspected carefully and retested at the time. Since then the control rod assembly process has also been improved, and supervision of assembly and quality control have been stepped up. The cause of the current anomaly is being investigated.

The NSRPA is overseeing the investigation and will assess the results and the proposed measures. The NRG will not restart the HFR until the NSRPA has given its approval. The NSRPA does not yet have enough information to rate the malfunction on the INES scale.

1 September 2015: NRG other installations – Leak in DWT gas pipeline; INES rating not applicable

On 11 September 2015, the Nuclear Research and Consultancy Group (NRG) reported that, on 1 September 2015, a leak was detected in a gas pipeline in the basement of the Decontamination and Waste Treatment Facility (DWT). The leak was detected after an employee reported that the basement smelled of gas.  Measurements showed that there was indeed a slightly elevated concentration of natural gas in that area. The internal emergency organization was then alerted, and the gas supply was shut off. The fire brigade subsequently concluded that, having shut off the gas supply, the situation had been made safe.

Further investigation revealed that the pipeline in question was a branch that was no longer in use, and that had not been shut off properly. NRG has removed the branch and sealed the connection point in the correct manner. Due to this timely action, the gas concentration remained so low that no dangerous situation arose.

Following this incident, a number of points for improvement were identified in the management and inspection of pipelines. The site manager will check to see whether these aspects are also important for the rest of the site.

The Nuclear Safety and Radiation Protection Authority (ANVS) has determined that, in this case, The International Nuclear and Radiological Event Scale (INES) scale does not apply. This is because this incident was neither radiological nor nuclear in nature. The reason that the ANVS was, nevertheless, notified of this incident was that, according to the safety specifications, all incidents for which the internal emergency organization is alerted must be reported to the regulator.

27 August 2015: Urenco – Incident with filter material in production hall at enrichment facility; INES level 1 (provisional rating)

On 27 August 2015, Urenco reported that there had been an incident at its Almelo enrichment facility that morning. At the facility, natural uranium is processed ('enriched') for use as fuel in nuclear power plants. The enriched uranium is a low-level radioactive material.

The incident occurred in a filtering system in a room where enriched uranium is collected. No one was in the room at the time. Following the incident, a number of rooms were evacuated as a precaution and production was halted in the hall where the incident occurred. Production was also stopped in the adjacent hall, because it is directly connected to the hall where the incident occurred. As a result of the incident, uranium-containing material from the filtering system entered the production area and several adjacent rooms. An elevated concentration of low-level radioactive material was detected in the ventilation system leading to the roof of the production hall. Very small quantities of uranium were also detected on the roof of the hall. On the basis of the findings of survey measurements, Urenco has excluded the possibility of uranium having been dispersed into the environment.

Urenco is currently decontaminating its operating areas and investigating the cause of the incident. In response to the incident, Urenco has taken steps to enable production to continue in the other production areas.

The ANVS has performed a site inspection to establish the current situation. At the request of the ANVS, the RIVM is currently investigating the accuracy of the survey measurements performed by Urenco at the time of the incident. Investigations into the cause of the incident are in progress. The ANVS is supervising those investigations and will review plans to resume production in the relevant halls in due course. Production in those halls will not resume until the investigations are complete and resumption has been approved by the ANVS. The expectation is that that will take several weeks.

Update 17-12-2015

Urenco has now completed its investigation into the technical cause of the incident. Since the incident, Urenco has replaced all similar filters with filters of a different type, which are not liable to suffer from the same problem. The adjacent hall has been cleaned and, following a review of the evidential basis of the investigation's findings regarding the technical cause and an inspection relating to the radiological leak from the hall in question and the restart programme, the ANVS issued a Certificate of No Objection on 23 October 2015 for the resumption of production in that particular hall. The certificate was issued on the condition that Urenco performs a further study into possible underlying causes of the incident and critically reassesses the suitability of the new type of filter in the light of knowledge gained from the incident. The report on the RIVM's review of the measurements performed by Urenco and the work carried out to ascertain whether and to what extent radiation can be released into the exterior atmosphere is scheduled to be submitted to the ANVS in late 2015.

Cleaning of the hall where the incident occurred is still ongoing. The ANVS is carrying out inspections in order to supervise the radiological protection of personnel. Before production resumes, a Certificate of No Objection must be obtained from the ANVS for the hall in question.

On the basis of current estimates of the consequences, the ANVS has provisionally classified the event as INES level 1. This implies that there was an anomaly, because the radiological consequences of the leakage of a small amount of uranium within the hall and onto the roof are very minor, but that a safety barrier was nevertheless breached.

8 July 2015: NRG – Failure of part of the fire hydrant system at the Petten Research Facility – INES level 0 (provisional rating)

On Wednesday 8 July 2015 the NRG reported that leaks developed in the course of repair work to the fire hydrant system, resulting in part of the system being shut down. As a result the DWT (the NRG decontamination and recycling plant) and Mallinckrodt Pharmaceuticals among others were left without extinguishing water.

Compensatory measures were taken immediately. Alternative fire hydrant facilities were provided from another fire hydrant outside the affected sector, and it was agreed as a matter of procedure that any fire would be ‘escalated’ to the regional fire service at an earlier stage. The fire hydrant system was repaired on Friday 10 July 2015, whereupon the temporary measures were discontinued.

During the period of reduced fire hydrant availability the ANVS kept abreast of developments at Petten. The NRG is carrying out an investigation to ascertain what caused the leaks and what measures need to be taken to avoid such leaks in future. The ANVS is overseeing the investigation and will assess the results and the proposed measures.

Based on the information available so far the ANVS has provisionally rated this event as INES level 0 (no safety significance); as based on the information currently available it is assumed that an unsafe situation did not occur, since compensatory measures were taken immediately. A final rating will be assigned once the results of the investigation have been assessed. It may be appropriate to raise the event to INES level 1 if the investigation shows, for example, that the event was caused by inadequate maintenance.

7 July 2015: NRG/HFR – Fault in reactor shutdown system – INES level 0

On 7 July 2015 the NRG reported that an investigation had shown that two of the HFR’s six control rods had a longer drop time than permitted. During normal operation control rods are not lowered into the reactor, or only partially. The drop time is the time for which the control rods are fully dropped into the reactor (after a drop signal is given).

The control rods halt the nuclear fission process in the reactor. They drop in the event of a process control malfunction. The maximum drop time is laid down in the Safety Specifications. The NRG has discovered that the malfunction was caused by a faulty switch (relay) in the shutdown system.

Following the notification the ANVS actively consulted with the NRG, asking it to substantiate the reliability of the entire shutdown system before restarting the HFR. The NRG has provided that substantiation. The NRG has replaced the relay concerned and taken additional measures to detect faults of this kind even faster in future. The ANVS then informed the NRG that the restriction on restarting the HFR had been lifted.

The NRG is carrying out an investigation to ascertain how the switch became faulty and whether the fault could have been been discovered sooner, and to determine what measures need to be taken to avoid such faults in future. The ANVS is overseeing the investigation and will assess the results and the proposed measures.

The ANVS has rated this event as INES level 0 (no safety significance), as an unsafe situation did not occur, since generous safety margins are built into the control rod drop time and it was still possible to safely shut down the HFR with the four remaining control rods (which did drop on time).

28 May 2015: EPZ – Incorrect timing of calibration of the backup emergency cooling water system – INES level 0 (provisional rating)

On 28 May 2015 EPZ reported that on 27 May 2015 the flow meter of Borssele NPP’s backup emergency cooling system had been calibrated at a time when that was not permitted. This meter may only be calibrated when the reactor is shut down and the fuel is in the opened reactor vessel (RPV). In this case, however, it was calibrated while the fuel was in the fuel pool. This was an infringement of the requirement laid down on the subject in the plant’s Technical Specifications (TS).

The purpose of the backup emergency cooling water system is to extract cooling water from the groundwater beneath the facility in an emergency when no cooling water is available from the river Western Scheldt. The flow meter measures the amount of emergency cooling water supplied in such cases.EPZ is investigating the underlying cause of this deviation of the TS.

The ANVS is overseeing the investigation and will specifically check whether the investigation considers the fact that there have been several recent cases of calibration work being carried out at times when this was not permitted (see the 17 November 2014 notification).

The ANVS is overseeing the investigation and will assess the results and the proposed measures. Based on the information available so far the ANVS has provisionally rated this event as INES level 0 (no safety significance), as an unsafe situation did not occur, since adequate alternative cooling systems were available during the event and the situation concerned lasted only a very short time. A final rating will be assigned once the results of the investigation have been assessed. It may be appropriate to raise the event to INES level 1 if the investigation shows that the event is of a recurring nature and not enough has therefore been learned from previous events.

20 May 2015: EPZ – Period of suboptimal cooling longer than envisaged – INES level 0 (provisional rating)

On 20 May 2015 EPZ reported that complications had occurred when lifting the lid of the reactor vessel at Borssele NPP, which was out of service at the time for the annual fuel change. The pulley block of the crane had skewed, causing cables to foul the block. It was therefore decided to lower the lid to its original position. Lifting was not recommenced until the lifting gear had been modified and reinspected by an independent inspection authority. Lifting was carried out under tighter supervision on the part of the supplier and the inspection authority and nothing unusual was observed.

The result of this delay was that the reactor was approximately 12 hours longer in mid-loop than originally scheduled during the fuel change. Mid-loop is an operating condition in which the fuel remains in the reactor vessel and is cooled normally but less water is temporarily available in the cooling system for that cooling. In that operating condition there is less time to correct the situation if the cooling system fails, so it is kept as short as possible. The unscheduled longer time spent in this operating condition was therefore reported to the ANVS as an abnormal event.

EPZ is investigating the cause of the crane fault and is to take measures to prevent repetition. The ANVS is overseeing the investigation and will assess the results and the proposed measures. Based on the information available so far the ANVS has provisionally rated this event as INES level 0 (no safety significance), as based on the information currently available it is assumed that an unsafe situation did not occur. A final rating will be assigned once the results of the investigation have been assessed.

13 May 2015: EPZ – NPP shut down on account of technical faults in the emergency power supply – INES level 1 (provisional rating)

On 13 May 2015 EPZ reported that it had been ascertained in regular tests of the emergency power supply that various individual emergency power batteries did not meet the capacity requirements, as laid down in the Technical Specifications (TS). As this official requirement was not met the NPP was taken out of service and its annual scheduled maintenance was brought forward.

In the meantime EPZ has demonstrated to the ANVS that during operation the emergency power battery package as a whole have always met the minimum capacity required under the licence, so no unsafe situation had occurred. The emergency power batteries supply the NPP’s control and safety systems with power so that the plant can be taken out of service safely in the highly exceptional case that the many other power sources that are available would have become unusable (for example owing to a natural disaster).

In the meantime the emergency power batteries concerned have been replaced. EPZ has demonstrated to the ANVS’s satisfaction that the batteries will meet the capacity requirements for at least the forthcoming operating period of the reactor (one year). Following approval by the ANVS the NPP was restarted on 11 June 2015. EPZ is investigating the cause of individual batteries ageing faster than the factory warranties would lead one to expect.

The ANVS is overseeing the investigation and will assess the results and the proposed measures.Based on the information available so far the ANVS has provisionally rated this event as INES level 1 (anomaly), as availability of the emergency power batteries was reduced during operation.

As many reactors use this type of battery, the ANVS has published this event in the IAEA database of malfunctions in power reactors (IRS). This will enable other countries to investigate the situation in their own NPPs.

27 March 2015: NRG – Failure of the external power supply – INES level 0

On 27 March 2015 the NRG reported that failure of the grid supply in North Holland had caused an emergency power situation at the Petten Research Centre, where the NRG operates not only the High Flux Reactor (HFR) but also some other nuclear facilities, such as the Hot Cell Laboratories (HCL) and the Waste Storage Facility (WSF).

In response to the failure of the grid the NRG put the Facility’s emergency response plan into action. In the event of a disaster the plan ensures a safe and prudent response to unforeseen circumstances. The HFR was shut down as a precaution and the diesel generators provided the emergency power supply. The regular power supply was restored during the afternoon, whereupon the NRG resumed regular operation of all the systems under controlled conditions.

Although the cause of this event lay beyond the NRG’s control, the organization was required to report it because the Facility’s internal emergency response plan had been put into action. During the day the ANVS kept abreast of developments at Petten, and it is monitoring the evaluation being carried out by the NRG in response to the event. The ANVS has rated this event as INES level 0 (no safety significance), as the systems were shut down under controlled conditions and the emergency organization came into action.

24 and 26 March 2015: NRG/HCL – Malfunction in the radiological monitoring system – INES level 0 (provisional rating)

On 31 March 2015 the NRG reported that on Tuesday 24 March 2015 (during the daytime) and Thursday 26 March 2015 (at night) a malfunction occurred in the radiological monitoring system which monitors any release of radioactive materials from the cells of the Hot Cell Laboratories (HCL) in the event of an incident. The malfunction was found to have been caused by a faulty relay in the HCL’s power supply.

During these malfunctions the NRG evacuated the HCL as a preventive measure (on 24 March 2015) and banned staff from entering them (on 26 March 2015).

As the ventilation of the cells was functioning normally at the time of the malfunctions, any radioactivity released could not have escaped unfiltered, and there were therefore no emissions into the outside air. The faulty relay was replaced. The part of the emergency power supply concerned is to be inspected thoroughly in the light of this malfunction. The NRG will take additional measures if necessary based on the findings of this investigation.

The ANVS is overseeing the investigation and will assess the results and the proposed measures. Based on the information available so far the ANVS has provisionally rated this event as INES level 0 (no safety significance), as the correct measures (including evacuation) were taken and there was at no time any chance of radioactive materials being dispersed outside the facility.

27 February 2015: Urenco – Overfilled cylinder of uranium hexafluoride – INES level 0

On 19 March 2015 Urenco reported that it had been ascertained when weighing a cylinder of uranium hexafluoride (UF6) that the cylinder had been filled with more UF6 than permitted. The cylinder concerned had been overfilled owing to an anomaly in the filling system’s weighing device. This was discovered during the weight check carried out as standard practice after filling.

Events of this kind must be reported to the ANVS within 30 days. The event took place on 27 February 2015, so Urenco reported it on time. After discovering the overfilling Urenco transferred the excess UF6 to another cylinder under controlled conditions, and it is investigating the underlying cause of this event.

The ANVS is overseeing the investigation and will assess the results and the proposed measures. The ANVS has rated this event as INES level 0 (no safety significance), as the ‘double measurement’ system ensures that an overfilled cylinder cannot leave the building.

10 February 2015: NRG/HFR – Alert level for radioactivity monitoring in the reactor hall set too high – INES level 0 (provisional rating)

On 10 February 2015 the NRG reported that a High Flux Reactor (HFR) operator had discovered during a check that the system for monitoring the level of radioactive materials in the air of the reactor hall had been set too high. This monitoring system is part of the reactor safety system. Both the level at which a warning alarm should go off and the level at which the reactor should shut down automatically were set too high. The levels set were almost 40% higher than those permitted under the Technical Safety Specifications. The anomalies were discovered during the monthly outage. The NRG corrected the anomalies and checked the settings of the other reactor protection systems before restarting the reactor.

If an incident had occurred while the settings were too high in which radioactive materials had been released into the reactor hall this would not have resulted in emissions into the environment, as the reactor hall acts as an airtight containment chamber.

The NRG is carrying out an investigation to ascertain how and when this anomaly occurred. The ANVS is overseeing the investigation and will assess the results and the proposed measures.Based on the information available so far the ANVS has provisionally rated this event as INES level 0 (no safety significance), as the HFR has various systems to detect malfunctions in the production process in good time and there was at no time any chance of radioactive materials being dispersed outside the facility.

5 February 2015: NRG/HFR – Leak of tritium-contaminated water into the ground due to a filling hose becoming detached – INES level 0

On 5 February 2015 the NRG reported that on 3 February 2015 an estimated one to three cubic metres of tritium-contaminated water leaked into the ground on the site of the High Flux Reactor (HFR). Tritium is a radioactive material. The leak was due to a filling hose becoming detached while pumping water from an interim storage tank to a tanker. The water was groundwater that had been pumped up from the HFR site as part of the cleanup of the site after a leaky underground pipe had been discovered in 2012. The radioactivity of the water was 24.3 MBq per cubic metre. As a reference, the limit above which cleanup is required for the HFR site is between 0.1 and 7.4 MBq per cubic metre, depending on the precise location. During the cleanup process contaminated groundwater is taken by tanker to the DWT (the NRG decontamination and recycling plant) for processing.

The NRG is investigating the cause of the filling hose becoming detached, also including an examination of system components with the same technical construction. The NRG is also looking into improvement measures for emptying the tanks.

The ANVS is overseeing the investigation and will assess the results and the proposed measures. The ANVS has rated this event as INES level 0 (no safety significance), as the impact of this event was limited. There was no dispersal of tritium outside the site, and the current cleanup process will substantially reduce the amount of tritium in the soil of the site.

26 January 2015: NRG/Transport – Incomplete listing of radionuclides in transported radioactive materials – INES level 0

On 26 January 2015 the NRG reported that questions had been posed by the recipient concerning the composition of the waste material in a shipment of radioactively contaminated resin to a processing plant in the UK. The NRG uses resin to collect radioactive materials from the cooling water of the High Flux Reactor (HFR). The method involves radioactive materials accumulating in the resin. The resin was transported to the UK for processing. On arrival, radioactive materials that had not been listed on the transport documents were found to be present in the resin. The resin had been packaged in line with the requirements, and the materials not listed were not measurable on the outside of the transport packaging, so the incomplete listing did not have any impact on transport safety.

The NRG is investigating the cause of this incomplete listing and the possible consequences for future shipments, which cannot now be carried out under the current licence for trans frontier waste shipment.

The ANVS is overseeing the investigation and will assess the results and the proposed measures. The ANVS has rated this abnormal event as INES level 0 (no safety significance), as there was at no time any danger to workers or the environment.

19 January 2015: NRG/Transport – Excessive radioactivity in transport package – INES level 0

On 19 January 2015 the NRG reported that the transport packaging of radioactive material dispatched by the NRG had been found to contain more radioactivity than allowed under the transport regulations. This related to three containers of Yttrium-90, an isotope used for medical purposes. Yttrium-90 is an isotope that decays relatively fast: the amount halves over a few days as a result of radioactive decay.

The NRG is investigating how this anomaly was able to occur. The ANVS is overseeing the investigation and will assess the results and the proposed measures.The ANVS has rated this event as INES level 0 (no safety significance), as this limited infringement of the transport regulations did not have any consequences.