Leak from primary coolant system at Kakrapar Atomic Station-1

Print View Posted on: 19 November 2018

Event Date: 11 March 2016 Event Type: Power Reactor
Event Location: India, KAKRAPAR-1 INES Rating: 2 (Final)

On March 11, 2016, at 0852 hrs, Kakrapar-1 experienced an event of leak from a pressure tube. Following the event, reactor underwent automatic shutdown and all the safety systems provided in design for core cooling and containment isolation functioned as intended. There was no fuel failure due to the event.

Following the event, at 0910 hrs, plant emergency was declared as per an established procedure. This was terminated after safely defueling and isolating the leaky pressure tube from primary coolant system on March 21, 2016. During the course of plant emergency, environmental survey within the site as well as in the off-site domain up to 30 km was carried out. No increase in air borne activity or radiation level was observed. There was no radiological impact on plant workers, public and environment due to the event. The event was categorised as ‘Small LOCA’.

Root cause analysis of the event revealed that Kakrapar-1 had operated with an unlisted impurity (ethylene) in carbon dioxide gas which is used in leak detection system of pressure tubes. This led to corrosion on the outer surface of all the pressure tubes in the reactor and leak from the affected pressure tube.

The event is rated at level 2 on INES.

INES Rating: 2 - Incident (Final) as per 19 November 2018
Release beyond authorized limits? No
Overexposure of a member of the public? No
Overexposure of a worker? No

Contamination spread within the facility? No
Damage to radiological barriers (incl. fuel damage) within the facility? No

Degradation of Defence In-Depth Yes

Person injured physically or casualty? No
Is there a continuing problem? No
Related Information
AERB Press Release (804kb)

Vivek Piplani
Atomic Energy Regulatory Board

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