2(H H H₂  ) 2H₂O₂ O₂ 2H₂O 8H₂O radiation 2H₂ O₂ 6H₂O 2H₂O radiation 2H₂ O₂ radiation 2H₂O 2H₂ O₂ radiation EFFECTS OF RADIATION DOE-HDBK-1015/2-93 Reactor Water Chemistry ON WATER CHEMISTRY (SYNTHESIS) CH-03 Rev. 0 Page 4 (3-8) (3-11) Net reaction: or (3-12) The net result of these reactions is simply the decomposition of water.  If H   and O   are allowed 2 2 to escape from solution as gases, the reaction continues as written.  If, however, the water is contained in a closed system under pressure (as in a reactor coolant system), H   and O   are 2 2 confined,  and  an  equilibrium  state  is  reached  because  radiation  also  causes  the  reverse  of Reaction  (3-2)  to  take  place.      Primarily  neutron  and  gamma  radiation  induce  both  the decomposition  of  water  and  the  recombination  of  H    and  O    to  form  water.    Thus,  it  is 2 2 appropriate to write Reaction (3-2) as a radiation-induced equilibrium reaction. (3-12) To arrive at the overall effect of radiation on water, the above process involved the assumption that only one reaction pathway is available to each reactive species.  This was done primarily for convenience because inclusion of every possible reaction in the summation process becomes rather cumbersome.  Even if all the reactions are taken into account, the net result is the same as Reaction (3-12),  which is reasonable because inspection of Reactions (3-3) through (3-11) shows that the only stable products are H , O , and H O (H O   and OH  combine to form water, 2 2 2 3 + - and H O  decomposes at high temperature).  Perhaps not as obvious, more water is consumed 2 2 than is produced in these reactions, and the net result is the initial decomposition of water that proceeds until equilibrium concentrations of H   and O   are established. 2 2 Before  discussing  the  effects  of  radiation  on  other  processes,  chemical  equilibrium  in  the presence of ionizing radiation should be mentioned.  Equilibrium processes in aqueous solutions are discussed briefly in Module 1, which states that temperature influences the equilibrium. Ionizing radiation also influences the equilibrium of these solutions.