VT Padmanabhan*, Dr R Ramesh, Dr V Pugazhendi

Introduction

Post Fukushima, NPCIL appointed separate task forces consisting of nuclear experts to examine all the commercial nuclear power plants, including the yet to be commissioned reactors at Kudankulam.  The committees for MAPS and KKNPP were headed by S Krishnamurthy, a senior official at MAPS.  Both these stations are located in Tamil Nadu coast off Bay of Bengal.  MAPS has two 220 MW(e) pressurized heavy water reactors (PHWR) and KKNPP has two pressurized water reactors (PWR),  MAPS is 65 km from Cehnnai, KKNPP is 60 north of Kanyakumari.

Same Eco-system – different levels of risks

Madras Atomic Power Station

Kalpakam and Kudankulam are located on the Bay of Bengal coast.  Though there is a distance of about 400 km, both the sites share the hazards of the bay more or uniformly.  However, the KKNPP report shows that the Kudankulam coast is less vulnerable to the elements in comparison with Kalpakam.  For the worst case scenario, the MAPS committee considered 2004 Sumatra tsunami and 1977 cyclone with landfall in Andhra Pradesh.  KKNPP committee considered 2004 tsunami and “five storms with maximum wind speeds ranging from 61 to 114 kmph recorded in (the) region during the period from 1891 to 1986.”  There were more intense cyclones in Southern Bay of Bengal, the one that hit Chennai in Nov-Dec 1996 lasted for 9 days ‘reported to be very long life compared to any cyclone in the Indian Ocean’.

“The water level experienced at (KKNPP) site during the December 26, 2004 tsunami was only about 2.2 meters above mean sea level.”  The flood level experienced at MAPS during the same tsunami was 10.5 meters.

KKNPP task force considered flooding of 5 meters above mean sea level in their worst case scenario.  This includes 2.5 meters from a future tsunami and 2.5 meters from a cyclone.  Their wall is 8 meters high, reactors, turbines, steam generators are all below 9 meters MSL.  The task force says there is a buffer of 4 meters.

The MAPS expert committee used a different calculation.  In their own words: “For MAPS, …taking into account 1977 severe cyclone at Andhra, the safe grade level from cyclonic storms had been arrived at as 10.45 m. Hence for the purpose of this analysis, a flood level of15 meters is taken. If at a later date, this figure gets revised on further review, the new figures can be adopted, to revise the analysis.  While KKNPP group considered both the tsunami and the cyclone, MAPS  group forgot to include tsunami in their equation.

Since the MAPS committee anticipates a flood level of 15 meters MSL, many of the structures will be under water.  Yet, the reactors will be shut down safely, core and spent fuel pool will be cooled.  At KKNPP the experts concluded that since the flood level will be 5 meters under worst case scenario and since all the buildings are above 8 meters, there is no threat to any structures from any natural calamities during the next 1000 years.

Water Backup

It was pointed out in our last dispatch that the total water reserve in 11 tanks at KKNPP is 10,200 cubic meters, sufficient enough for running two reactors for one and a half days. At MAPS “enough water storage for 7 days operation is available at on-site reservoir (9 million gallons) and even assuming no make-up this can be extended to few more days during the shutdown.” A liter = 0.2642 US gallon.  So the total water reserve at MAPS is 34 million liters or 34,000 cubic meters. (This reserve they say is good enough in keeping the reactors safe for seven days in the case of a station black out.) The installed capacity at MAPS is 440 MW(e) as against 2000 MW(e) at KKNPP. Reserve water per MW in these two campuses are:

  • KKNPP     =   5.1 cub meter

  • MAPS       =77.3 cub meter

Even though the reserve water available with MAPS is 15 times higher than KKNPP, the MAPS task force recommended constructing a new water tank with a storage capacity of 750 cub meters.  KKNPP task force did not mention a word about additional water reserves at Kudankulam.

MAPS draws its water from Palar basin some 15 km away from the campus through pipe line. At KKNPP, sea water is desalinated and if the desalination plants fail, the nearest source of fresh water is Pechiparai dam, 65 km away from the plant.  In case of an emergency, if all the young people is Kanyakumari and Tirunelveli volunteer themselves, pipe-line can be laid in a day or two.  If pipes are also available.

This quick review of two task force reports, both headed by one person shows that

  1. the flood water level in the worst case scenario is about three times lower at KKNPP than at MAPS.  This is not incorrect, if the strength and behavior of the anticipated natural calamities are similar to the reference events.

  1. Future tsunami will impact on KKNPP and not on MAPS.

  1. KKNPP reactors will be able to survive without harming the operating personnel, their families and the people of peninsular India and Sri Lanka at large, even though the water reserve per unit electricity is less 8% of that in MAPS.

 

Conclusion

The Nuclear Regulatory Commission in USA also had constituted an expert committee to review the safety of 104 operating reactors in that country.  The experts found that the regulatory regime is just a ‘patchwork’.  The committee made 12 solid recommendations, 7 of them are being implemented.  In comparison to the US committee, the Indian response is rather weak.  Because there were seven committees, each looking at one campus alone.  In spite of this, it is good to read them.  Because these reports contain a long list of recommendations for short-term and long term implementation. These recommendations are being studied.

 

 

 

 


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References

S.Krishnamurthy, M.Ramasomayajulu  R.R.Sahaya, S.Chandramouli (2011) SAFETY EVALUATION OF INDIAN NUCLEAR POWER PLANTS PHWRs AT MADRAS ATOMIC POWER STATION (MAPS)

S. Krishnamurthy, U. S. Khare, K. R. Anilkumar, Suresh Kumar Pillai, R. K. Gupta. (2011)  INTERIM REPORT OF TASK FORCE ON SAFETY EVALUATION OF THE SYSTEMS OF KKNPP POST FUKUSHIMA EVENT