UNBUILDING AN ATOMIC GI­ANT

IN­SIDE THE BIG­GEST NU­CLEAR POWER PLANT TEAR-DOWN IN THE U.S.

Popular Science - - THE FAULT IN OUR STAR -

1 COOL IT

At the San Onofre nu­clear power plant, work­ers trans­fer 2,668 fuel as­sem­blies— hold­ing 1,109 met­ric tons of ra­dioac­tive ura­nium-235—to 17-foot-tall stain­lesssteel con­tain­ers. These sit in­side a deep, steellined cool­ing pool for sev­eral years, chill­ing at tem­per­a­tures around 68 de­grees Fahren­heit, un­til work­ers can move them to stor­age.

2 ENTOMB IT

Af­ter the fuel cools, work­ers fit the can­is­ters into 20-foot-deep con­crete casks em­bed­ded in the ground. The con­crete helps trap the fuel’s ra­di­a­tion in­side, while vents cir­cu­late air to keep it cool. These casks, which will be mon­i­tored and guarded around the clock, are strong enough to with­stand earth­quakes, tsunamis, even the im­pact of a jet crash.

3 RIP IT

Re­motely con­trolled tools cut up the highly con­tam­i­nated equip­ment (less than .04 per­cent of the de­bris). Other ro­botic ma­chines will re­move the most tainted waste. Then work­ers—us­ing hy­draulic ham­mers, saws, and bull­doz­ers—rip apart the build­ings. Mun­dane of­fice ma­te­ri­als like shelv­ing, fur­ni­ture, and in­su­la­tion fill out the junk pile.

4 SHIP IT

De­mo­li­tion pro­duces more than 25 mil­lion cu­bic feet of de­bris— re­bar, con­crete, and pip­ing—enough to fill a de­cent-size col­lege­foot­ball sta­dium. The San Onofre site hosts up to 60 rail cars at a time, wait­ing to cart off the low-level ra­di­a­tion de­bris. Trucks haul the non­tainted stuff—75 per­cent of the to­tal—to land­fills in Texas and Ari­zona.

5 BURY IT

Freight cars carry the low-level ra­dioac­tive de­bris—now packed in drums, bags, and large con­tain­ers—to a nu­clear-waste land­fill in the Utah desert. Work­ers there check and doc­u­ment ra­di­a­tion lev­els, then bury the stuff in “em­bank­ments,” from 8 feet be­low grade to 38 feet above grade, in sed­i­men­tary rock and cov­ered in clay and rock. —MBG

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