The government is announcing an additional £350 million-worth of funding for the next stage of designing the future generation of British nuclear-armed submarines.
This investment will sustain 1,200 UK jobs and follows the initial £350 million of design work announced earlier this year, the Ministry of Defence (MoD) said.
Hammond will make the announcement on a visit to the home of the UK's nuclear deterrent at Faslane on the River Clyde in Scotland.
Commenting on the Scottish independence debate, the Defence Secretary reiterated the Government's commitment to keep the naval base in Scotland, saying he was "confident" Scottish people would choose to remain part of the UK.
He said: "We are confident that the Scottish people will choose to remain part of the United Kingdom. The Faslane complex is the largest employment site in Scotland with over 6,500 jobs underpinning the local economy.
"We have no plans to move the nuclear deterrent from the Clyde. On the contrary, we intend to move the Astute and Trafalgar Class attack submarines to Faslane, creating a further 1,500 jobs. The Scottish Government needs to explain how their policy would benefit Scotland's economy and safeguard Scottish jobs."
The announcement followed the successful firing of an unarmed Trident ballistic missile by HMS Vigilant during a test launch in the Atlantic Ocean last week, the MoD said.
HMS Vigilant is one of four Vanguard Class submarines which maintain the UK's nuclear deterrent.
The Vanguard submarines will be replaced from 2028 by the Successor which is currently being designed by British companies. As a result of today's announcement, BAE Systems will proceed with an additional £315 million worth of work, with a further £38 million carried out by engineering support services company Babcock.
Hammond said: "Our continuous submarine-based nuclear deterrent is the ultimate safeguard of our national security and the Government is committed to maintaining it, both now and in the future.
"The test firing and further investment in replacing the deterrent demonstrates that commitment. This latest expenditure for the next generation of nuclear-armed submarines is an investment in UK security and the British economy, sustaining high-quality jobs and vital skills."
First Sea Lord Admiral Sir Mark Stanhope said: "The Royal Navy has for over 43 years continuously operated the UK's nuclear deterrent to stringent safety standards and HMS Vigilant's latest test firing before she returns to the patrol cycle reflects that successful deterrence is based upon strong determination.
"One of the core roles of the Royal Navy, the Continuous At Sea Deterrent, remains an enduring strategic capability, underpinning our nation's commitment to the preservation of peace in our uncertain world."
A senior Liberal Democrat source said: "There has been no change in policy on Trident. This is just some detail around the announcement of funding that was made back in May 2011.
"The crucial decision on maingate and whether there will be a like-for-like replacement for Trident will not be made until 2016.
"The Liberal Democrats will continue to make the case for alternatives to a like-for-like replacement. Our current review into those alternatives will report next year."
All Royal Navy submarines will be based at Faslane by 2017, including the Astute and Trafalgar class attack submarines, which - along with the Sandown Class Mine Counter Measure vessels - will increase the workforce at the site to more than 8,000 by 2022.
SNP MSP Bill Kidd, a vice-president of Parliamentarians for Nuclear Non-proliferation and Disarmament, said: "For the UK Government to boast about spending hundreds of millions of pounds on weapons of mass destruction - while at the same time implementing brutal welfare cuts and slashing investment in the economy - is obscene.
"More than that, Philip Hammond's weak attack on the Scottish people's choice in the independence referendum continues to use fantasy figures relating to the number of jobs associated with Trident at Faslane. His own Ministry's figures, obtained through FoI, show that there are not thousands of jobs dependent on the nuclear weapons system but 520 - all of which and more will be taken up by Faslane continuing as the main Scottish naval base."
Hammond said the nuclear upgrade at Faslane will protect the UK from many threats, including terrorist groups, until well into the second half of this century.
"The continuous at sea deterrent has been operated for the last 43 years," he told BBC Radio Scotland's Good Morning Scotland programme.
"The plans that we have now will take us well into the second half of this century.
"You can't say with any certainty today who will be threatening us in 20, 30, 40 or 50 years' time.
"That is why it is so irresponsible to play games with a strategic deterrent like the UK nuclear deterrent.
"It is there to protect our nation, all the people of the UK, against any threat, whether it comes from another major power, or whether it comes from a rogue nuclear state, or whether it comes from a terrorist group."
He insists that the UK Government "is not making specific contingency plans for a yes vote" in the referendum, but said it has "all sorts of contingency plans for maintaining the deterrent in place in all sorts of circumstances".
He accused the SNP of "picking their figures very selectively" in claiming that Trident supports just 520 jobs, maintaining that there will be more than 8,000 civilian and military jobs at Faslane by the end of the decade, including contractors working for the base and "a multiplier effect across the local economy".
Deputy Prime Minister Nick Clegg said: "Having seen the papers this morning, I think some people are jumping the gun on this Trident decision.
"The Coalition Agreement is crystal clear - it will not be changed, it will not be undermined, it will not be contradicted.
"The final decision on Trident replacement will not be taken until 2016, however much other people may not like it that way."