Capitol Hill Happenings: Today in Congress

The House and Senate return for their first full day in Washington since the announcement of a deal on a spending measure for the rest of the fiscal year. Staffers on the House Appropriations Committee worked into late into the night finalizing the legislative language for the budget blueprint, which trims $38 billion from current spending levels. It should be ready for a floor vote later in the week.

The 2012 budget proposed by House Budget Committee Chairman Paul Ryan, R-Wisc., is scheduled for a floor vote on Thursday. The plan overhauls the Medicare and Medicaid entitlement programs, alters the tax code, and drastically trims government spending. Ranking Member Chris Van Hollen, D-Md., will discuss the Ryan plan off campus at an event at the Center for American Progress. Van Hollen has called the Republican proposal part of "the same old ideological agenda."

Sens. Ron Wyden, D-Ore., and Dan Coats, R-Ind., outline their tax reform proposal at a Progressive Policy Institute symposium. Their plan lowers tax rates and simplifies the tax code.

Mississippi Governor and potential 2012 presidential candidate Haley Barbour speaks to the Congressional Health Care Caucus at 12:00 p.m. ET. He'll talk about the Medicaid reforms he introduced in 2005 that reduced his state's Medicaid roles for three consecutive years and brought state and federal spending on the program to 4 percent from 16 under his predecessor.

Japanese authorities have upgraded the severity rating of the nuclear disaster at the country's Fukushima Daiichi nuclear plant. Officials now say the catastrophe could be as severe as the 1986 explosion and fire at the Chernobyl nuclear plant in the Ukraine. Environmental Protection Agency Administrator Lisa Jackson and Nuclear Regulatory Commission Chairman Gregory Jaczko testify on the implications the continuing calamity could have on the nation's nuclear facilities.

We'll be following these stories and more, so be sure to stay with Fox News for all the latest.