Task force for extra caution on old, new nuclear plants

An interim report of a Government task force has suggested greater safety measures at existing and upcoming nuclear reactors to pre-empt a Fukushima-like episode.

In the wake of the disaster in Japan earlier this year, the Government, as a measure of abundant caution, is looking to increase safety measures in upcoming projects based on the latest 700-MWe indigenous pressurised heavy-water reactors (PHWRs) and the 1000-MWe Russian-designed reactors coming up in Koodankulam.

Worst-case scenarios

The task-force report, set up to evaluate safety of the four 700-MWe indigenous PHWRs on the anvil and the two Russian reactors that are close to commissioning, discusses the worst-case scenarios, including lack of power and disruption of water-supply routes in a reactor.

Suggestions being reviewed for implementation include incremental water availability in case of accidents and aspects of alternate power supply, including renewable power backup.

The report is a result of two additional task forces formed by Nuclear Power Corporation of India Ltd, apart from four panels constituted earlier for a review of existing stations, to assess safety of the new set of reactors under construction.

“The new 700-MWe PHWRs are capable of handling any postulated external natural events. However, some considerations are being reviewed in detail for feasibility of implementation,” an official said. The engineering details of these additional measures are being worked out, the official said.

For water supply during accidents, the report suggests additional design provisions including arrangements to utilise on-site water resources. Besides, having fire tenders for the backup of diesel-driven-fire water pump and bore holes inside the plant boundary have been suggested.

On alternate power supply, the report said apart from the 4-by-4,000-kW emergency diesel generators that is part of the station design additional design provisions like extra power packs and power sources for monitoring, emergency loads and lighting should be considered.

Measures to prevent escalation of accidents and arrest them at various stages, too, have been suggested.

In case of Koodankulam, the review said the project design has incorporated sufficient “passive systems” to ensure core-cooling and radioactivity-confinement, even in the case of an extended unavailability of electric power.

The report has suggested provision of solar-powered lighting for buildings and a study on the feasibility of using wind-power generators already available at the Koodankulam site as backup.

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