If China has produced thousands of warheads in past, that would mean those are the heavy warheads (weight more than 1000kg's) meant for liquid-fueled missiles what are being removed from service right now, and are too large for new generation solid-fueled missiles.
Of course there is always possibility that their new warheads use HEU instead of Pu, but if they do then you can forget 10 RV DF-41 ICBM because HEU weapons are bigger than their plutonium counterparts. HEU production is also much more difficult to detect especially if manufacturing happens in underground factory, and we know that Chinese bought new centrifuge technology in 1990's. Chinese first thermonuclear weapons used HEU instead of Pu, so it's not unknown bomb making material for them.
Here is few reason why Chinese may have gone back to HEU in 1990's.
-The half-life of uranium 235, due to radioactive decay, is 700 million years versus 25,000 years for plutonium 239. Therefore, the radioactive hazards associated with uranium pit fabrication would be reduced.
The radioactive hazards of weapon handling by DOE and military custodians could be reduced.
-Plutonium is pyrophoric. Uranium is not.
With a 700 million year half-life, there should be no pit aging problems.
-Given an accident and a uranium spill, decontamination could be less demanding.
-The larger critical mass required by the use of uranium will result in thicker pit shells, thereby reducing machining problems during fabrication and resulting in higher yields and lower fabrication costs.
And here are the problems if there is a need to stuff as many MIRVs in missile as possible, but i'd assume that large ICBM like rumored DF-41 would not have any problems to carry three HEU warheads.
Bob Peurifoy, a retired Sandia National Laboratories scientist, thinks that now that fewer weapons are needed aboard each missile, uranium offers a viable alternative to plutonium.
According to a calculation Peurifoy provided to the Journal, as much as six times as much uranium and high explosives would be needed for his uranium bomb. With other changes to the weapon, he calculated a 13-inch diameter plutonium primary could be replaced by a uranium alternative about 20 inches in diameter. That would allow three uranium warheads to be carried by a Trident II submarine missile, according to Peurifoy. The missiles now carry eight plutonium warheads.
According to a story in Global Times, on June 21, 2013 China successfully produced the first batch of enriched uranium using its own centrifuges. The existence of the centrifuge facility in Lanzhou, Gansu Province that uses a technology developed in China, was first reported in 2010. The enrichment plant, which is owned by the China National Nuclear Corporation (CNNC) is estimated to have the enrichment capacity of about 0.5 million SWU/year. It appears that the plant will be producing low-enriched uranium for power reactors.
I'm just entertaining myself, no need to take my writings too seriously.
