AECL provides information on heavy water event

AECL provides information on heavy water event:
http://www.aecl.ca/NewsRoom/Community_Bulletins/2013/130822.htm

“The following information bulletin is in accordance with Atomic Energy of Canada Limited’s (AECL) commitment to enhance its voluntary public disclosure of events related to the Chalk River Laboratories (CRL). The subject of this public disclosure is the unrecoverable loss of approximately 11 kg or 10 litres of heavy water. During routine work activities on the afternoon of Tuesday, August 20, a spill of approximately 250 kg of heavy water from the Fuel Rod Flask occurred at the storage block area within the NRU facility.  The Fuel Rod Flask is used in the fuelling and de-fuelling of the reactor and the movement of other reactor components.  The water-filled storage block is used for temporary storage and cooling of fuel rods exiting the NRU reactor. AECL’s response to the spill was immediate and according to established protocols. Mitigation measures were effective in ensuring worker safety, preventing heavy water loss and recovering heavy water. During the response, the conservative decision was made to reduce staffing levels within the facility to a minimum complement. Normal staffing for the facility resumed that evening. While most of the heavy water has been recovered, a loss of approximately 11 kg has been measured through monitoring. The heavy water loss resulted from evaporation through the facility’s ventilation system. This heavy water contains trace amounts of the radioactive isotope, tritium, for which the Canadian Nuclear Safety Commission (CNSC) has established weekly regulatory release limits. The airborne release of tritium as a result of this incident was well below the regulatory limit, measured at 0.2% of the limit. This loss of heavy water has no safety consequences. AECL has identified that the source of the spill was the connection point between the storage block and the Fuel Rod Flask. Corrective actions are underway and the facility is expected to resume normal operations in the near future. This incident has been reported to the CNSC. There was no impact on AECL's ability to safely monitor or operate the reactor. At no time did this event result in safety consequences to workers, the public or the environment.”