My Blogs : First Opinion ; Radiation Protection Issues ; My Voice

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Thursday, August 30, 2007

Kashiwazaki-Kariwa Nuclear Plant (Japan)–Damage due to earthquake on 16th July, 2007

Earthquake damage to the Kashiwazaki-Kariwa nuclear power station (largest in the world, run by the Tokyo Electric Power Company , Japan) on 16th July 2007 appears to be limited and less than expected, according to an IAEA expert report on the incident. The design of the plant was not qualified to withstand earthquake of 6.8 magnitude that occurred.

In particular, the reactors, Units 3, 4 and 7, which were at full power, were shut down automatically probably due to the conservatisms introduced at different stages of the design process (design safety margins). Safety related structures, systems and components of the plant seem to be in a general apparently good condition, much better than might be expected for such a strong earthquake, and there is no visible significant damage, the report stated.

While the plant's nuclear components appear to be in a satisfactory state, non-safety related structures, systems and components were affected by significant damage such as soil and anchorage failures and oil leakages. There were two minor releases of radioactive material occurred after the quake. The first one was a release of radioactive material from the main turbine condenser through the main stack and the other was some leakage of contaminated water from the spent fuel pool to a non-controlled area, which was later pumped to sea. It was noted that there was some delay in reporting the releases to the authorities.

Some of the suggestions made in the report are: i) a re-evaluation of the seismic safety the Kashiwazaki-Kariwa NPP using updated criteria and methods and addressing the issue of the potential existence of active faults underneath the site, ii) the potential interaction between large seismic events and accelerated ageing to be considered in future inspection programmes and iii) communication of the investigation findings and lessons learned to other nuclear operators, regulators and technical support organizations.

Friday, August 10, 2007

IN A NUTSHELL, THE INDO-US NUCLEAR DEAL MEANS:

• The 123 agreement (as per the Section 123 of Atomic Energy Act of 1954) allows US to sell nuclear fuel and nuclear technology to India for civilian purposes. The agreement, approved now by the Indian Cabinet, is reported to be in consonant with the Hyde Act passed in 2006.
• India will get nuclear fuel from America to run the nuclear power reactors (PHWRs), at full capacity. This is in spite of the fact that India is not a signatory to Nuclear non-Proliferation Treaty (NPT).
• India is required to separate nuclear facilities for civilian and military use.
• India can continue to reprocess spent nuclear fuel from its civilian reactors. However, the spent fuel from the safeguarded reactors will be reprocessed in a separate reprocessing facility under international safeguards.
• In the event of India testing any nuclear weapons, the supply of nuclear fuel / technology will be terminated by the US. The supplied fuel may have to be returned. Not sure of the political consequences of the test. US may assist to procure fuel from some other countries of the 35 member Nuclear Suppliers Group (NSG) for continued operation of the civilian reactors producing commercial power.
• Finally, the deal could open-up the presently dormant nuclear power related American business to the tune of US$100billion.
• India gets much needed nuclear power, which is environmental friendly.