Method to analyze economics of asset management solutions for nuclear steam generators

• US 7,810,991 B2
• Filed: 11/05/2009
• Issued: 10/12/2010
• Est. Priority Date: 06/21/2006
• Status: Active Grant

• Current Assignee: Areva NP Incorporated (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Areva NP Incorporated (French Alternative Energies and Atomic Energy Commission)
• Inventors: Colgan, Kent, Griffith, John Carroll, Pop, Mihai G. M.
• Primary Examiner(s): Boswell; Beth V
• Assistant Examiner(s): Kardos; Neil R
• Application Number:
  US12/612,741
• Publication Number:
  US 20100145756A1
• Time in Patent Office: 341 Days
• Field of Search: 705/8, 374/7, 374/43, 374/44, 374/102, 374/141
• US Class Current: 374/7
• CPC Class Codes: F01K 13/02 Controlling, e.g. stopping or starting
• CPC Class Codes: F22B 37/002 specially adapted for nuclear steam generators, e.g. maintenance, repairing or inspecting equipment not otherwise provided for
• CPC Class Codes: G06Q 10/063 Operations research, analysis or management
• CPC Class Codes: G06Q 10/06375 Prediction of business process outcome or impact based on a proposed change
• CPC Class Codes: G06Q 10/20 Administration of product repair or maintenance
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

A method to determine corrective actions of a nuclear steam generator, having the steps of modeling of steam generator tube and deposit heat transfer characteristics by analytically deriving specific deposit characteristics and descriptive model parameters, wherein the modeling uses historical thermodynamic data for an operating plant under evaluation, identifying a set of one of preventive and corrective maintenance alternatives to accomplish steam generator deposit objectives, determining through the modeling a power production impact of each of the set of one of preventative and corrective maintenance alternatives to determine an economic cost for each of the set of preventative and corrective maintenance alternatives, and initiating a maintenance alternative with a lowest economic cost as compared to the maintenance evaluation alternatives with higher economic costs.

Claims

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;

2. The method according to claim 1, wherein the maintenance alternative performed on the steam generator is selected from the group consisting of operating the steam generator for a time, t, before performing maintenance, operating the steam generator at reduced power, chemical cleaning, upper bundle flush, enhanced upper bundle flush, sludge lancing, and combinations thereof.

3. The method according to claim 1, further comprising predicting future power production levels using the calculated future evolution in time of at least one of the deposit porosity, steam channel tortuosity, deposit thermal resistance, deposit copper content, and deposit thickness.

4. The method according to claim 3, further comprising determining costs for replacement power.

5. The method according to claim 1, wherein the historic data comprises at least one of steam pressure in the nuclear steam generator under operating conditions, primary system hot and cold leg temperatures, in-service heat transfer tube surface area, and steam generator thermal power.

6. The method according to claim 1, further comprising obtaining and testing a deposit.

7. The method according to claim 6, further comprising determining one or more of the deposit thermal resistance, deposit thickness, deposit porosity, and tortuosity of a steam channel in the deposit layer.

8. The method according to claim 6, wherein the deposit is obtained by at least one of scraping and lancing a heating surface of steam generator tubing.

9. The method according to claim 6, wherein the B-base fouling factor is calculated from measurements taken from the deposit.