Nuclear security remains top dog in the Department of Energy’s $27.9 billion budget request for 2015 released Tuesday, but what that means for Los Alamos National Laboratory’s bottom line remains uncertain until details are released in a few days.

The Department of Energy budget covers renewable and fossil fuel energy programs, electric grid security, energy innovation, and protecting and maintaining the nation’s nuclear arsenal.

Of the total department budget request, $11.9 billion is for the National Nuclear Security Administration’s programs and administration, which cover the lion’s share of Los Alamos National Laboratory funding each year. The NNSA is looking at ways to be more efficient, given problems with runaway costs on some of its nuclear weapons and stockpile projects, officials said during a news conference Tuesday.

All told, New Mexico received more than $4.6 billion in Department of Energy funding in fiscal year 2014, most of it for LANL and Sandia National Laboratories.

The complete breakdown of Department of Energy funding for 2015 by state, facility and program was not released Tuesday.

The bulk of the NNSA request — $8.3 billion — is for the weapons program, an increase over last year. An additional half-billion dollars are available for weapons activities through the Opportunities, Growth and Security Initiative, if it’s approved by Congress.

Meanwhile, the administration asked for a 20 percent reduction in funding for nuclear nonproliferation, at $1.6 billion. A lot of the decrease is to temporarily suspend construction of a facility in Aiken, S.C., to process plutonium pits from old nuclear warheads into fuel for nuclear power plants. The facility is part of a plan to break down and process 34 metric tons of plutonium materials from Russia and the U.S.

Just one portion of the project has run $3 billion over budget, and the full life-cycle cost was projected at $30 billion.

Los Alamos National Laboratory was helping to break down the plutonium pits and converting them to plutonium oxide as feedstock for the Savannah plant. The lab was planning to process at least 10 metric tons by 2018, but that will be delayed. NNSA officials said they’ll spend at least the next year reviewing the best way to process the plutonium.

Los Alamos National Laboratory also is the only site processing plutonium into new pits for nuclear warheads. The lab and NNSA have been trying for years to build a new facility for testing and making the pits. The lab has two main plutonium facilities, one that is aging and scheduled to be closed by 2019 and the other — PF-4 — needs work to make it safer.

The administration is looking at revamping the pit production program at the lab in three phases. The first phase in 2015 doesn’t involve any new facility money, according to Don L. Cook, NNSA deputy administrator for defense programs. Any request for new funding to retool the existing Plutonium Facility 4 at the lab and potentially build small production modules would occur in 2016 in the third phase, he said.

Greg Mello of the watchdog Los Alamos Study Group said the Department of Energy budget and its impact on the lab is a reminder. “In New Mexico, it is a big mistake to depend on Cold War weapons programs as a prop for our economy, let alone as a source of growth,” he said in a statement. “There just isn’t going to be significant growth in those programs, ever, and eventually there will be decline in real terms.”

The Department of Energy budget request reduces funding for environmental management to clean up legacy radioactive waste at LANL by $171 million. The department still is asking for more than $224 million to remediate or remove the waste, left over from the lab’s founding era during the Manhattan Project and the Cold War.

The Energy Department has proposed reducing the environmental management budget by $695,000 for the Waste Isolation Pilot Plant in Carlsbad, in the news lately for evacuating employees and shutting down recently after the facility’s first radioactive leak was detected.

The environmental management budget totals more than $5.5 billion to clean up 50 years worth of highly radioactive waste at more than 20 sites in the U.S. It is the largest such program in the world, according to the Department of Energy.

Other Department of Energy budget highlights:

u $118 million requested for a new office of Environment, Health, Safety and Security, which is supposed to protect the safety of federal employees, contractors and communities near Department of Energy facilities and ensure documents pertaining to weapons of mass destruction are not released to the public.

u $355 million for a new climate resilience fund.

u $200 million for programs to modernize the electric grid.

u $714 million for energy efficiency and renewable energy.

Contact Staci Matlock at 505-986-3055 or Follow her on Twitter @stacimatlock.