"People's Daily" is not very good at providing English language translation.
Yet it is sufficient to "read between the lines" and understand what they are saying.
Normally, nuclear fuel used for power generation are considered "spent" when the energy they emit falls below a certain level, even though they are capable of still providing energy. Similarly, nuclear power plants gain efficiency by operating at high temperature/pressure levels.
What the Chinese are apparently doing is finding a way to economicly utilize the lower energy that is still given of by so called "spent" fuel, making use of the lower temperatures generated at a lower (perhaps even atmospheric) pressure. (Very hot water rather than steam) The lower temperature and pressures involved in turn lower the cost of constructing other components of the system.
Granted, it is difficult to tell exactly what they are doing from a technical perspective. But then, even our own journalists are generally technologicly imcompetent to communicate such information.