The New York Times published and article New Doubts About Turning Plutonium Into a Fuel, which provides a summary of the issues with the U.S. MOX plutonium disposition program. Most of these issues were covered in this blog, most recently in U.S. plutonium disposition program: Uncertainties of the MOX route.
The New York Times also reports on other serious problems with the MOX plutonium disposition route. In order to facilitate the program, the NRC exempted nuclear power stations that burn MOX from the security requirements that cover handling of special nuclear materials. Also, Shaw Areva Group, the primary contractor of the MOX Fuel Fabrication Facility (MFFF), "requested an exception to the government's material control and accounting standards for plutonium." The NY Times reports that the company later withdrew the request. However, the fact that this request was made illustrates the challenge of ensuring proper material control and accounting in the program that is supposed to handle 34 tonnes of weapon-grade plutonium.