[DNFSB LETTERHEAD]

March 28, 2006

Mr. Mark D. Sullivan

Carter Ledyard & Milburn LLP

2 Wall Street

New York, New York 10005-2072

Dear Mr. Sullivan:

I am writing in response to your letter to me dated January 17, 2006, regarding plutonium production at the Idaho National Laboratory Advanced Test Reactor (ATR). In your letter, you requested, on behalf of your client, Keep Yellowstone Nuclear Free (KYNF), that the Defense Nuclear Facilities Safety Board (Board) investigate the safety of ongoing and proposed operations at the Department of Energy’s (DOE) ATR located at the Idaho National Laboratory. You also stated that KYNF considers the ATR to be unsafe and forwarded to me your letter to the DOE dated December 21, 2005, which detailed KYNF’s concerns and provided comments on the Draft Environmental Impact Statement for the Proposed Consolidation of Nuclear Operations Related to Production of Radioisotope Power Systems.

The Board’s jurisdiction extends to defense nuclear facilities as they are defined in 42 U.S.C. § 2286g as being production or utilization facilities under the control or jurisdiction of the Secretary of Energy and operated for national security purposes. At this time, ATR is not operated for national security purposes; consequently, ATR is not a defense nuclear facility subject to the Board’s oversight.

It is the practice of the Board, when information comes to the attention of the Board that pertains to matters not under the Board’s jurisdiction and would be of use to other officials, to refer such information to the appropriate officials. I appreciate your informing me of KYNF’s concerns and note that your letter to DOE dated December 21, 2005, provided KYNF’s concerns to the appropriate officials in DOE.

Sincerely,

A. J. Eggenberger

Chairman

c. The Honorable Samuel W. Bodman

The Honorable Linton Brooks

Mr. Mark B. Whitaker, Jr.