U.S. most vulnerable reactor: Indian Point 3, N.Y.

Change in risk: N/A.

17. Three Mile Island 1, Middletown, Pa.: 1 in 25,000 chance each year. Old estimate: 1 in 45,455. Change in risk: 82 percent.

18. Palo Verde 1, Wintersburg, Ariz.: 1 in 26,316 chance each year. Old estimate: N/A. Change in risk: N/A.

18. Palo Verde 2, Wintersburg, Ariz.: 1 in 26,316 chance each year. Old estimate: N/A. Change in risk: N/A.

18. Palo Verde 3, Wintersburg, Ariz.: 1 in 26,316 chance each year. Old estimate: N/A. Change in risk: N/A.

18. Summer, Jenkensville, S.C.: 1 in 26,316 chance each year. Old estimate: 1 in 138,889. Change in risk: 428 percent.

22. Catawba 1, York, S.C.: 1 in 27,027 chance each year. Old estimate: 1 in 33,333. Change in risk: 23 percent.

22. Catawba 2, York, S.C.: 1 in 27,027 chance each year. Old estimate: 1 in 33,333. Change in risk: 23 percent.

24. Watts Bar 1, Spring City, Tenn.: 1 in 27,778 chance each year. Old estimate: 1 in 178,571. Change in risk: 543 percent.

25. Indian Point 2, Buchanan, N.Y.: 1 in 30,303 chance each year. Old estimate: 1 in 71,429. Change in risk: 136 percent.

26. Duane Arnold, Palo, Iowa: 1 in 31,250 chance each year. Old estimate: N/A. Change in risk: N/A.

27. McGuire 1, Huntersville, N.C.: 1 in 32,258 chance each year. Old estimate: 1 in 35,714. Change in risk: 11 percent.

27. McGuire 2, Huntersville, N.C.: 1 in 32,258 chance each year. Old estimate: 1 in 35,714. Change in risk: 11 percent.

29. Farley 1, Columbia, Ala.: 1 in 35,714 chance each year. Old estimate: 1 in 263,158. Change in risk: 637 percent.

29. Farley 2, Columbia, Ala.: 1 in 35,714 chance each year. Old estimate: 1 in 263,158. Change in risk: 637 percent.

31. Quad Cities 1, Cordova, Ill.: 1 in 37,037 chance each year. Old estimate: 1 in 71,429. Change in risk: 93 percent.

31. Quad Cities 2, Cordova, Ill.: 1 in 37,037 chance each year. Old estimate: 1 in 71,429. Change in risk: 93 percent.

33. River Bend 1, St. Francisville, La.: 1 in 40,000 chance each year. Old estimate: 1 in 370,370. Change in risk: 826 percent.

34. Peach Bottom 2, Delta, Pa.: 1 in 41,667 chance each year. Old estimate: 1 in 120,482. Change in risk: 189 percent.

34. Peach Bottom 3, Delta, Pa.: 1 in 41,667 chance each year. Old estimate: 1 in 120,482. Change in risk: 189 percent.

36. Crystal River 3, Crystal River, Fla.: 1 in 45,455 chance each year. Old estimate: 1