Constellation Energy Group and its nuclear joint venture partner, Electricite de France, announced Monday that they will move quickly to close their $4.5 billion nuclear joint venture, though the deal leaves some unanswered questions.

Among them: when each of Constellation's Baltimore Gas and Electric residential customers will receive a one-time $100 credit, one of several conditions imposed by Maryland energy regulators last week.

"We are analyzing the order, and the commission's requirements relating to the customer credit, and will announce our plans just as soon as we complete that process," Constellation spokesman Rob Gould said.

Other issues left unresolved include the location of EDF's new U.S. headquarters in Maryland, the scope of Constellation's future charitable giving, and the construction of a visitor center and new nuclear unit at Calvert Cliffs.

On Friday, the state Public Service Commission approved Constellation's $4.5 billion deal to sell half of its nuclear power business to EDF. But regulators added conditions such as the ratepayer credit totaling $110.5 million and measures to protect BGE from future financial troubles of its parent company.

The commission directed the company to implement the credit before March 30 to offset winter heating bills.