Defense Secretary Chuck Hagel will announce on Friday a comprehensive overhaul of the Pentagon’s nuclear weapons programs, after scandals in the Air Force and Navy this year prompted scrutiny, a defense official said.

The problems prompted Hagel to call for two reviews of the nuclear weapons programs early this year, and they outline a variety of deficiencies.

“While our nuclear arsenal remains safe, secure and effective today, the reports tell us we must take action now in order to ensure that remains the case in the future,” the official, who requested anonymity, said Thursday night.

After the announcement, Hagel is expected to travel to Minot Air Force Base in North Dakota, where Air Force officials oversee an arsenal of nuclear bombs that can be dropped from aircraft and nuclear missiles that are kept in underground silos that were built during the Cold War, and have seen few upgrades since. The defense official did not say why Hagel selected Minot as the site of his visit.

News of the overhaul, first reported by the Associated Press Thursday night, had been anticipated for months. The AP reported that the reports call for billions in upgrades to invested in support systems to keep the weapons reliable, and for the Air Force to put a four-star general in charge of its nuclear force, known as Global Strike Command. It’s currently a three-star position.

Hagel called for the two reviews in late January, after an embarrassing scandal in the Air Force in which dozens of officers overseeing nuclear missiles at Malmstrom Air Force Base in Montana had been caught either cheating on a monthly launch proficiency test, or knew about others who did and did nothing to stop it.

Shortly afterward, Navy officials disclosed a similar problem, saying they were investigating about 30 senior enlisted sailors for allegedly cheating on tests required to operate nuclear reactors that power both ships and submarines. They were tipped off by a sailor who served at nuclear-training program in Charleston, S.C. Thirty-four sailors ultimately were expelled.

The Air Force has been active since their scandal broke, launching an internal investigation of where their two legs of the so-called nuclear “triad” — submarines, long-range missiles and bombers — needed work. In an unprecedented move, nine commanders in the missile force were removed from their jobs and a 10th resigned in March.

More recently, two additional commanders in the missile force were fired, the Associated Press reported earlier this month. One of them served at F.E. Warren Air Force Base in Wyoming; the other was at Minot.

At the same time, Air Force Secretary Deborah James and Lt. Gen. Stephen Wilson, chief of Global Strike Command, have said they will do whatever they can to change the culture in the nuclear force.

Beginning Oct. 1, missile launch officers became eligible to receive up to $300 incentive pay per month — an attempt by senior officials to underscore the importance they see the mission having. The Air Force also issued new uniforms, cold-weather gear and personal protective equipment to security force troops guarding the missile silos this year after they raised concerns about them during the review.

This post has been updated to correct the amount of Air Force commanders fired recently.