Author : Stephanie A. McKee
Publisher :
Page : 159 pages
File Size : 11,40 MB
Release : 2008
Category :
ISBN :
Book Description
(Cont.) The radioactive volatiles which remain in the primary comprise only tritium, two isotopes of iodine, two isotopes of tellurium, and three isotopes of cesium. These species deposit on primary surfaces to a great enough degree to preclude hands-on primary system maintenance. In addition, techniques for removal of volatile and radioactive species from the primary coolant were identified, and a scheme for purification of the primary coolant volume was selected. The analysis confirms that primary coolant activity can be maintained at acceptable levels when purification of the primary coolant volume occurs once per hour. The response of the vent system to changes in primary system pressure was also investigated. In particular, the small periodic pressure transients known as breathing were studied, as were loss-of-coolant type scenarios. Both cases were investigated using hand calculations and computational techniques, and the radiological consequences of each were addressed. The analysis demonstrated the ability of the vented fuel assembly to quickly equalize pressure in the event of a sudden drop in operating pressure, and also showed the ability of a succession of plena to prevent the expulsion of much of the activity inventory of the plena during a breathing transient. Conversely, the use of a single plenum results in reduced activity release during a LOCA. After consideration of both results, a two-plenum approach, with a large lower annular plenum following a small upper axial plenum, was selected as the final design.