Sen. Pete V. Domenici (R-N.M.), chairman of the Senate Budget Committee, rejected a plan that conservative senators are drafting to bring a pending $1-trillion fiscal 1987 budget more in line with what President Reagan wants. Domenici, appearing on NBC's "Meet the Press," made his comments as the Senate prepared for its second week of budget debate. An alternative being drafted by Sen. Phil Gramm (R-Tex.) would add about $10 billion for military spending over a bipartisan proposal before the Senate and increase domestic spending cuts. Domenici dismissed Gramm's plan, saying: "I would predict, as I've told him, that it won't get 30 votes."