The State-run Nuclear Power Corporation of India Limited (NPCIL) clarified here on Friday that all nuclear power reactors at the Rajasthan Atomic Power Station (RAPS) were “safe” and that there was no radioactive leakage from any of the units. Denying reports that two workers had been taken into observation after being exposed to high doses of radio-active tritium, NPCIL’s Executive Director (CP &CC) Nalinish Nagaich said: “….all nuclear power reactors are safe and there has not been any radioactive leakage to the environment, as is being reported in certain section of the media”. Of the six units at the NPCIL-managed RAPS, unit-I was under long shutdown, while four other units - units-2 to 4 - are operating and the unit -5 was under start-up after completion of planned biennial shutdown. The unit-6 is under maintenance. Nagaich said that on June 23, 2012, an incident of tritium uptake of above Investigation Level (4 M/Bq/l) occurred in the Unit-5 of RAPS while it was under planned biennial shutdown. “The Investigation Level of the tritium uptake is defined conservatively at about 1/10 the of the authorized annual limit specified by the regulatory body. The incident was immediately reported to Atomic Energy Regulatory Board (AERB), Nagaich said. According to Nagaich, the incident has been investigated by the committees deputed by NPCIL and AERB independently. “The appropriate measures as suggested by these committees to prevent such incidents in future, will be implemented promptly,” he said. The units at RAPS are Pressurised Heavy Water Reactors (PHWRs) which use natural uranium as fuel. According to Nagaich, the June 23, 2012 incident occurred when a modification work, as planned during the shutdown, for assuring a provision of alternate water addition to the moderator system in the Reactor -5 was being carried out. “The uptake occurred due to inadvertent rise in tritium levels in a localised area of the containment building of the reactor -5. The localised increase in the Tritium concentration occurred due to the opening of the moderator cover gas line where the welding jobs were to be performed,” Nagaich pointed out. “There was absolutely no release of radiation to the environment. The workers are continuing to perform their normal duties, albeit in other areas of the station,” Nagaich said. “All the persons involved in the work were monitored as a regular practice. Two persons are likely to exceed the annual exposure limits specified by the regulatory body. The exposure of other persons is below the annual exposure limit specified. They have been assigned the work in non- radioactive areas as per the prevailing procedure applicable in such cases, the NPCIL official added.