A physicist looks at nuclear reactor safety Richard

A physicist looks at nuclear reactor safety Richard Wilson Mallinckrodt Professor of Physics (emeritus) Harvard University UNM April 1 st 2001

Take an old reactor of oudated design Subject it to an earthquake not seen for 3 centuries Add a Tsunami of a size not before seen Disconnect from the grid YET as I will show no one gets radiation sickness No identifiable or attributable cancer Only a handful of CALCULATED cancers This poves that nuclear power is safe. OR DOES IT?

1939 Nuclear fission discovered (Hahn and Strassman) Neutron chain reaction possibility shown! (Joliot, Halban and Kowarski) Euphoria! The "nuclear age" had come! UNM April 1 st 2011

10, 000 times more energy per unit weight of fuel compared to coal. Less mining Chemical processing before use possible Chemical processing after use possible Waste can be kept out of the environment Even if only U 235 (0. 7%) is used a factor of 100, 000 But bombs 10, 000 times more powerful are possible. UNM April 1 st 2010

Easy to make a nuclear bomb. Serber’s Los Alamos lectures 1943 Smythe report 1945 Harder to make a viable power reactor It depends on delayed neutrons for control No nation has a bomb made with reactor fuel in its arsenal

NEVER forget (or allow fear transference) August 1940 50 lbs of TNT destroyed a house and killed a man Sakharov’s Nuovo Zembla test was 50 megatons equivalent TWO BILLION TIMES GREATER!

The possible Nightmare Theft or "Diversion" of enough fuel to make abomb 9 countries have made bombs None have a bomb made with reactor fuel IIS TOO EASY TO DO IT DIRECTLY A world wide nuclear power community can create the openness that is a major (maybe ultimately the only) deterrent UNM April 1 st 2011

The energy from burning is more concentrated in a nuclear reactor. We run at a power level so that water can take the heat away make steam and generate electricity. This concentration makes it cheaper than other ways of boiling water

The early GE design Oyster Creek (196 something) Fukushima 1971 opeartion 35 in USA

Easy to shut down a reactor in an accident. BUT After nuclear fission has stopped: heat is still 8% of full power Wigner-Wey law 1951 or so After 10 hours it is 1% But not down to 0. 1% for a year. We need to remove this heat or the fuel will melt and release radioactivity FUNDAMENTAL RULE!! NEVER LET THE FUEL BE DRY

Ordinary Engineering thinking Try it. If it fails fix it. Set a “standard”. We can and must do better, Nuclear Power has led the way in thinking about large accidents 1949 DEFENSE IN DEPTH 1976 FORMAL EVENT TREE ANALYSIS We must still learn from experience

Multiple Barriers between fuel and us Fuel in pellets which hold much of it pellets in zircium rods which are tight rods in water in pressure vessel in containment BUT Keep water there to cool First barrier matters most

UNDERSTANDING HISTORY “He who does not understand history is condemned to repeat it” What have we learned? And what will we learn from Fukushima? UNM April 1 2011

We have learned: Acute radiation sickness when white blood cell count drops pecipitously (LD 50 250 Rems or with blood transfusion 350 Rems) Die within a month (Louis Slotin 1945 etc

If someone gets a dose just less than 200 Rems over a period of years then he or she has a 10%-20% addition to his cancer rate. This of course is about what one gets from cigarette smoking. NO INDIVIDUAL can be identified from the Chernobyl area who we know got his cancer from radiation. For low doses we calculate probabilistically We should do this also for chemicals, air pollution etc. but do not always do so

On Saturday 12 th March the operators had no outside help All helicopters doing more important work no one to immediately reconnect electricity By Thursday March 17 th electricity reonnected helicopters available. Water started cooling eveything My prediction (made first on March 12 th): Few, maybe no one will get Acute Radiation Sickness. With no large cesium releases the number of CALCULATED cancers will be close to zero

Effect of accidental doses. Radiation dose of 300 Rems (3 Sv) or more within a week leads to ACUTE RADIATION SICKNESS the body fails within weeks. At Chernobyl about 200 plant workers and firemen got this much and officially 31 died. No one in the general public got acute radiation sickness. This happened at no other nuclear power accident

Effect of accidental doses. Radiation dose of 300 Rems (3 Sv) or more within a week leads to ACUTE RADIATION SICKNESS the body fails within weeks. At Chernobyl about 200 plant workers and firemen got this much and officially 31 died. No one in the general public got acute radiation sickness. This happened at no other nuclear power accident

At Fukushima All operating reactors shut down when the eatrthquake came No offsite power: but battery operated emergency systems and emergency diesels worked for 1 hour (maybe more) Then water boiled away till after an hour or to fuel began to melt at 1900 degrees F zirconium oxidizes leaving hydrogen behind WHY DID THEY DELAY PUTTING IN SEA WATER? Salt water corrodes and the plant will never operate again

This should have been learned from TMI It was drummed into me in 1971 by Manson Benedict Effects; (1) One can no longer work close to the reactor (2) SOME radioactivity releases

FORGOTTEN the health hazards of evacuation WHO about 1975 5% increase of cancer due to stress EXPLICITLY mentioned in Rogers report after TMI NO research on this! (but my group at Harvard looking at advantages of marriage)

PUBLIC PERCEPTION DOMINATES NUCLEAR CONSTRUCTION COSTS

PUBLIC PERCEPTION CHANGES 1973 Arab oil embargo 1979 Iraq- Iran war 2000 Climate change concerns 2011 Fukishima -North Cambridge

Windscale 1957(? 8) graphite burned, released iodine, Govt bought all milk for 2 months TMI 1979 reactor operators kept shutting off emergency system unecessary evacuation nuclear navy training inadequate for operators Chernobyl 1956 bad reactor design and operation initial explosion sent core into air (10, 000 feet and 30, 000 ft) subsequent graphite fire sent stuff 500 -1000 feet Fukushima 2011 most fuel stayed in place no driving force for spent fuel IF it evapored

Major disasters 500, 000 Fatal cancers caused by arsenic in drinking water in Bangladesh from exposures already accumulated 200, 000 Earthquake in Haiti 20, 000 Earthquake and Tsunami in Japan Fatal cancers from Chernobyl in next 60 years (calculated probabilistically) 4, 000 in Belarus, Russia and Ukraine 20, 000 world wide 6, 000/yr Cancers from Natural Background in US 0 Cancer fatalities from Three Mile Island My prediction 0 -1 from Fukushima

THE MEDIA PANICKED ON WEDNESDAY. I DID NOT (1) The staff at the Fukushima power plant seem to have got over the initial shock and seem to be behaving well and even heroically (2) The decay heat that must be removed has gone down from 8% of full power to less than 1% although it is now dropping more slowly (3) The hydrogen explosions have been outside the reactor containments and have not stopped cooling the core (4) More helicopters are now available from a multitude of international sources to do what is necessary (5) Although it is hard to get precise information from the power plants (I do not have the telephone number of the control room as I had at TMI) the Japanese are hiding nothing and are asking for help. (6) There is a reliable report that electricity has been available since Thursday at the plant site (7) The pessimistic report of NRC Chairman Jazco to a US Senate committee on Wednesday was contradicted by the Japanese because he had his facts wrong.

Fatal cancers caused by arsenic in drinking water in Bangladesh 500, 000 Earthquake in Haiti 200, 000 Earthquake and Tsunami in Japan 20, 000 plus delayed effetcs of stress and so on Fatal cancers from Chernobyl next 60 years (calculated) 4, 000 in Belarus, Russia and Ukraine 20, 000 world wide Fatal cancers from Natural Background in US 6, 000 per year Cancer fatalities (calculated) from Three Mile Island 0. 7 Calculated cancers from Fukushima 0 - 20 cancer increase from evacuation (1% or 1, 400)

URGENTLY reexamine all regulations tightened in panic after TMI and Chernobyl In emergency: Immediately allow 20 Rem per incident for many people 80 Rems for small number of volunteers (astronauts) EVACUATE up to 2 miles and more ONLY when large release happening EMPHASIZE do not drink local milk

A RELATED ISSUE If a nuclear bomb explodes: OR If a large source is exploded: CRITERIA or eentry should revert to recommendation of UK NRPB in April 1986 before the rules were tightened a factor between 30 and 50 by the panicked Europeans This will reduce the disturbance and make the potential terrorist action less attractive

Thank you for your attention My notes on Fukushima http: //physics. harvard. edu/~wilson/Japanese_reactors. html Physics is Fun - a memoire It is available from MIRA DIGITAL PUBLSHING of St Louis Missouri, USA http: //www. mirasmartshop. com/Physics-Is-Fun-Memoirs-of-a-Life-in-Physics_p_114. htm

1998 construction cost $1, 690 per MWe (GE reactor in Taiwan) four cents per k. Whe MUCH higher than $600/MWe -North Cambridge

THE THORIUM CYCLE 1959 Indian Point designed to allow thorium Thorium reserves = 6 x Uranium reserves -North Cambridge

Only uranium 235 fissionable by slow neutrons Only 3 suppliers Joachimstal, Czechoslovakia Union Minière, Congo Eldorado mining Co, Canada The "nuclear age" was to be short lived! -North Cambridge

GAS (1973) comes only with oil (1999) gas more plentiful EFFICIENCY (1999) Combined cycle X 2 Less greenhouse gases Few particulates -North Cambridge