in five deaths. In 1987 the machine was found defective by the Food and Drug Administration (FDA) and eventually recalled by AECL despite their multiple denials that the problems existed. 1990s Between 1990 and 1993, the 4 CANDU reactors at Darlington went online and represent the most recent reactor construction in Canada. In 1991, AECL decided to spin off its medical isotope production business under the name Nordion International Inc. The unit was sold to MDS Health Group and now operates under the name MDS Nordion With a contract signed in 1991, AECL, in partnership with MDS Nordion, began construction of the MAPLE dedicated isotope-production facility. Constructed on-site at AECL's Chalk River Laboratories this facility would house two reactors and an isotope processing facility. Each reactor was designed to be able to produce at least 100% of the world's medical isotopes, meaning that the second reactor would be used as a back-up to ensure an uninterruptible supply. The first reactor was started but experienced malfunctions in its safety rods, and a positive nuclear power feedback coefficient was recorded. After running over the Schedule by more than 8 years and more than doubling the initial budget, Unit 1 of the Cernavodă Nuclear Power Plant was commissioned on December 2, 1996. Rated at 706 MWe, it currently supplies approximately 10% of Romania's electrical needs. Unit Two achieved criticality on 6 May 2007 and was connected to the national grid on 7 August. It began operating at full capacity on 12 September 2007, also producing 706 MW. In the late 1990s, several reactors were built by AECL in South Korea. Wolsong 2 was commissioned July 1, 1997. Wolsong 3 was commissioned on July 1, 1998. Wolsong 4 was commissioned October 1, 1999. All three reactors were rated at 715MWe Gross Output. They currently have some of the highest lifetime capacity factors of nuclear reactors. 2000s In 2001, AECL began tests at Chalk River Labs to determine the feasibility of using surplus mixed oxide fuel (MOX) from the Russian and U.S. defence programs (which contains plutonium) as a fuel in CANDU reactors. Currently, AECL is developing the Advanced CANDU Reactor, or "ACR". This design is meant to improve the commercial CANDU 6 design in terms of capital cost and construction schedule, while maintaining the classic design and safety characteristics of the CANDU concept. Cernavoda Nuclear Power Plant Unit 2 began operation on May 6,