The hot run will start in a few days, says NPCIL Chairman and Managing Director

“Everything is on course” for the enriched uranium fuel bundles to be loaded into the first reactor of the Kudankulam Nuclear Power Project (KKNPP), Tamil Nadu, by the end of March and the reactor will be started up in April. “That is the target today,” said S.K. Jain, Chairman and Managing Director, Nuclear Power Corporation of India Limited (NPCIL).

“The hot run of the reactor will start in a few days. All the systems have already been individually commissioned. Some of the systems were commissioned in an integrated fashion when the cold run was done. Although this VVER-1000 reactor from Russia is the first-of-its-kind to be built in India, we have not come across any problem in the individual commissioning of the systems,” said Mr. Jain.

Control rods, numbering 121, have been successfully installed and tested. The control rods help in shutting down the reactor in case of an incident/accident. After the hot run of the reactor is completed, actual fuel bundles will be loaded into the first unit. The reactor now has dummy fuel bundles.

Two pressurised water reactors from Russia, each with a capacity of 1,000 MWe, have been built at Kudankulam by the NPCIL. The reactors use enriched uranium as fuel, and light (ordinary) water as both coolant and moderator. The NPCIL will operate the reactors.

Asked what a hot run entailed, the NPCIL Chairman said the reactor was practically ready for commissioning now. Before the real fuel bundles are loaded into the reactor, “we will run all the systems in an integrated manner at the operating temperature as if we are operating the plant,” Mr. Jain explained.

The only difference is that the reactor will have dummy fuel bundles in the hot run instead of actual fuel assemblies. Impurities in the system will be removed. Borated water will be circulated through the systems, which will be later drained of the water and dried. (Water mixed with boric acid is called borated water). Then the dummy fuel bundles will be removed and actual fuel assemblies loaded into the reactor.

M. Kasinath Balaji, Site Director, KKNPP, said, “We will keep the systems operating at normal operating temperature with the dummy fuel loaded into the reactor vessel. We will do safety tests and other elaborate tests. It is called hot run.” The vertical reactor vessel had 163 fuel assemblies, Mr. Balaji added.

Mr. Jain said the run-up to the criticality and the criticality itself of the pressurised heavy water reactors (PHWRs) operating in India were totally different from the Kudankulam reactors, which are pressurised water reactors.

The first consignment of light enriched uranium fuel for unit-1 of the KKNPP arrived at the site on May 25, 2008. This kind of fuel is in use in VVER-1000 MWe units in several countries since 1980s. The life-time fuel supply for the Kudankulam reactors is covered by a sovereign guarantee of the Russian Federation.

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