From KCNA:

The U.S. cites the life of the existing nuclear forces and their low technical efficiency as a main reason for developing the RRW. This is, however, nothing but a deceptive artifice to cover up its black-hearted intention. *The U.S. pretext to modernize nuclear weapons is too clumsy to convince people, taking into consideration the fact that the existing U.S. nuclear forces are confirmed to last more than a hundred years.*

*The U.S. loud-mouthed development of the RRW and the like are aimed at ensuring decisive upper hand in terms of strategic nuclear forces and thus prevailing over its major rivals and establishing an unchallenged domination over the world with nukes.* The world disturbance caused by the nuclear issue is attributable to the U.S. unreasonable policy of double standards.