Extension of HCDA safety analysis to large PCRV containment structures

The introduction of PCRV as part of LMFBR containment also brings in the need for dynamic analysis. The conventional design would not be adequate for designing PCRVs subject to highly transient loading. The PCRV models described provide a valuable illustration of the design arrived at by conventional means and loaded dynamically by means of the transient computer code. In particular the value of the computer code is realized in the case of the loop-type model. The original pressure-volume source used for the illustrative examples corresponds to a total available energy of 2720 MW-s, if the expansion were continued down to one bar. Thus the energy source is considerably larger than the energy releases utilized in the currently prevailing LMFBR safety evaluations. Although the resultant pressure acting on the walls of the PCRV varies with the particular design, the two sample cases indicate that no apparent difficulty is encountered in designing the PCRV to sustain those higher loads. The computer code is established as a valuable tool to study the PCRV response. It serves as a means to locate critical areas of the particular design. Parameter- or sensitivity studies could thus be made with great efficiency. As an example, one interesting and somewhat unexpected result of the illustrations presented is the occurrence of circumferential cracks through the walls of the PCRV