THE HTTR REACTOR PRESSURE-VESSEL AND ITS INTEGRITY AGAINST A PTS EVENT

Before manufacturing the real steel to be used in the reactor pressure vessel (RPV) of the high temperature engineering test reactor (HTTR) the vessel manufacturer and materials supplier made a sample steel by the same procedure as for the real steel (2.25Cr-1Mo) and conducted ma ny tests to obtain material strength data for its base and weld metals . The test results showed that the sample steel satisfied the HTTR des ign requirements. Vessel cooling panels are set on the inner surface o f the biological shielding concrete around the RPV, and are circulated with cooling water at 0.5 MPa and 40 degrees C to cool the shielding concrete during normal operation of the reactor. By supposing that the cooling panel breakes and the water discharges to the RPV outer surfa ce heated at 400 degrees C, the stress distribution generated in the v essel wall by a pressurized thermal shock (PTS) event can be calculate d using a finite element method code. This paper describes some of the results obtained from the material testing of the sample steel and th e estimated result using the scheme developed for a light water reacto r pressure vessel, to clarify the integrity of the HTTR-RPV under a PT S event. (C) 1997 Elsevier Science S.A.