2 Feb (NucNet): Canadian nuclear regulators have dismissed claims that radioactive material has leaked from a research reactor into the Ottawa River in the province of Ontario.

The Canadian Nuclear Safety Commission (CNSC) said allegations made in recent media reports arose out of two separate incidents involving leaks at the country�s National Research Universal reactor (NRU).

However, �at no time was the public or the environment at risk�, the CNSC said. �There is no radioactive material leaking into the Ottawa River associated with these leaks. CNSC has on-site staff that monitors the NRU and ensures that it operates safely and is in compliance with its licence conditions.�

In a statement on 28 January 2009, the CNSC said that on the evening of Friday 5 December 2008 Atomic Energy of Canada Ltd (AECL), which operates the NRU, discovered a �very small heavy water leak� that was confined to the NRU.

�AECL reported the event to the CNSC on Saturday 6 December 2008 and acted appropriately in delaying re-starting the reactor until the leak was investigated. Any water resulting from the leak was placed in storage tanks before being sent to the waste treatment centre at the Chalk River Laboratories.�

The CNSC said this leak has stopped and has not re-occurred. There was evaporation of some heavy water resulting in a small release of tritium through normal ventilation which was well below regulatory limits.

�Any water released into the Ottawa River is treated and monitored by AECL according to environmental standards,� the statement said.

Contrary to media reports, it did not take four days for AECL to tell the CNSC about the leak, said regulators. �The CNSC was made aware within hours of the leak and verified that it did not pose any significant risk to the public, workers or the environment.�

AECL officially submitted a preliminary report to the CNSC within 24 hours, in line with regulatory requirements. As is normal practice, AECL is required to continuously monitor for leaks from NRU�s cooling system and to take prompt action if a leak is detected. The CNSC has asked AECL to provide an update on the situation at the next scheduled public meeting of the CNSC on 19 February 2009.

The second leak referred to in the media reports involves light water leaking from the NRU reflector system, the CNSC said. �This water is collected by AECL and purified in the waste treatment centre. Therefore, there is no leak into the Ottawa River and there is no risk to the public or the environment.�

Details of the NRU incident and a diagram of the reactor is on the �current issues� section of the CNSC�s web site in English and French (http://www.nuclearsafety.gc.ca).

� by John Shepherd

>>Related reports in the NucNet database (available to subscribers)

�Lessons Learned� Report Into NRU Shutdown Outlines 15 Recommendations (News No. 61, 29 July 2008)

Canada�s NRU Returns To Service After Planned Outage (News in Brief No. 141, 15 December 2008)

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