As showing :n Fig 1 the reactor core is located at the bottom of the reactor pressure vessel (RPV) 6 primary heat exchangers divided mto two groups are arranged on the penpnery m upper part of the RPV The system pressure is maintained by N2 and steam All penetrations of RPV are therefore of small size (the largest one sized D50) and located at the upper part of RPV No pipe goes mside and down to the lower part of the RPV so that should a pipe break occurs outside the RPV the water ejection wall last not so long, then turn to steam ejection This arrangement reduces the amount of losmg inventory to a great extent Meanwhile a guard vessel fits tightly around the RPV so that the core will not become uncovered under any break of pnmarv pressure boundary even at the bottom of RPV This vessel can also function as a containment

The reactor vessel is cylindrical, with a weld hemispherical bottom head and a removable, flanged and gasketed hemispherical upper head The RPV is 4 8m in diameter, 14m in height and 197 Tons m weight The cylindrical portion of the vessel is welded by 65 mm steel plate then lmed with 6 mm stainless steel layer The RPV will be manufactured and fabricated in factory then shipped to the site The guard vessel consists of a cylindrical portion with a diameter of 5m and an upper cone portion with maximum 7m in diameter The guard vessel is 15 lm in height and 223 Tons m weight The upper and lower portions are fabricated m factory then shipped to the site separately, then welded together on site