Patent Document ID: 7810991
Application ID: 12612741
Patent Flag: 1

Claim One:
1. A method of maintaining a steam generator, the method comprising: obtaining at least one of historic and current data for at least one of a steam generator deposit porosity, ε, steam channel tortuosity, τ, deposit thermal resistance, K, deposit copper content, Cu, and deposit thickness, δ, for a steam generator or a steam generator of the same design; calculating a B-base fouling factor, B, from the at least one of historic and current data and at least one of: ɛ = ɛ 0 ⁢ ⅇ [ - t B ] , ⁢ τ = 1 + τ 0 ⁡ [ 1 - ⅇ [ - t B ] ] , ⁢ K = K 0 ⁡ [ 1 - ⅇ ( - t B ) ] , ⁢ Cu = Cu 0 ⁢ ⅇ [ - t B ] , and δ = M i ( 1 - ɛ ) ⁢ ( SD ) ⁢ ( A T ) , wherein M i is the deposit inventory mass, SD is the deposit solid density, A T is a tube bundle outside diameter surface area affected by deposition, t is the number of days since startup of the reactor or since the occurrence of a significant operational or maintenance event of the steam generator, B is a time constant describing parameter evolution, ε 0 is the maximum possible porosity, τ 0 is the maximum possible tortuosity, K 0 is the maximum possible resistance, Cu 0 is the maximum possible copper content, and ε 0 , τ 0 , K 0 , and Cu 0 are determined from available deposit data or design data for the steam generator; calculating the future evolution in time of at least one of the deposit porosity, steam channel tortuosity, deposit thermal resistance, deposit copper content, and deposit thickness using the calculated B-base fouling factor; determining remaining licensing life of at least one of the generator and generator changes from at least one of maintenance outages and modifications that affect corrosion susceptibility; determining available maintenance alternatives for the steam generator for remediation of the evolution in time of at least one of the deposit porosity, steam channel tortuosity, deposit thermal resistance, deposit copper content, and deposit thickness; determining the maintenance alternative having the lowest economic cost, based upon at least one of the net present worth, internal rate of return, and a payback period, and, optionally, is further based upon the cost of replacement power; and performing at least one of the maintenance alternatives on the steam generator.