European
Nuclear Society
e-news
Issue 17 Summer 2007
http://www.euronuclear.org/e-news/e-news-17/nps-kth.htm
In Sweden an innovative reactor design was developed during
the past decades. A reactor for district heating SECURE and a reactor for production
of electricity PIUS (Process Inherent Ultimate Safety)
SECURE and PIUS are innovative light water cooled reactors with passive safety
systems in a large pool of borated water in a concrete pressure vessel, located
underground. The irradiated fuel can be stored inside the reactor cavity for
thirty years. These features make the concept actual for today’s requirements.
An electrically heated test loop was built where the basic design characteristics were successfully verified. The concept was analyzed through detailed calculations with different computer codes.
Figure 1. The Operating Principles of the PIUS Pimary System
| A. |
A heat source (nulcear core) placed in a vertical pipe
in a water pool will cause an upward flow in the pipe. |
| B. |
If the heated water is returned to the lower end of the pipe there
is no net flow from and to the pool. |
| C. |
The heat generated can be extracted for a useful purpose. Mixing between
hot circulated and cold pool water is prevented by stable stratification
in tube bundles (density locks) |
| D. |
By placing the pool in a closed vessel and pressuring with a steam bubble above the circulation system the latter can be operated at high pressure and temperature. |
Figure. 2 The operating principles of the SECURE primary system.
Figure 3. Heated Reactor Secure-H and Prestessed Concrete Vessel.
Main Features of Nuclear Island.
Figure 5. The ATLE test rig.
|
National Heat Conference |
Fig 6. Schematic of the PLUS Reactor. Same
as Nuclear Safety article, Fig. 1, LA-UR-94-3467.
www.ornl.gov/info/reports/1991/3445603211254.pdf
September 1991
www.analys.se/lankar/bkgr/bkgr1-99.pdf
© European Nuclear Society, 2007
