US 7,444,246 B2 · System and method for determining fluctuating pressure loading on a component in a reactor steam dome

Abstract

A system and method for accurately estimating the fluctuating pressure loads on components, such as steam dryers, within a BWR steam dome using pressure time history measurements made on components of the BWR facility external to the steam dome. The method uses existing sensors to obtain the pressure time histories. An accurate determination of the fluctuating pressure loads within the steam dome may be obtained by modeling and analyzing the steam delivery system external to the steam dome, including all possible acoustic sources, using acoustic circuit methodology and pressure time histories, and then coupling these results, essentially as part of the boundary conditions, to the solutions for Helmholtz equation within the steam dome.

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Drawings

Claims41

Dependent claims

A method of determining a fluctuating pressure loading on at least one component inside a reactor steam dome having at least one steam line for transferring steam away from said dome, said steam line being joined to said steam dome via an exit region and having at least one acoustic source therein, said method comprising:

measuring pressure as a function of time at a first location in said steam line;
measuring pressure as a function of time at a second location in said steam line, wherein there is no said acoustic source between said first and second locations;
using said pressure measurements to calculate a fluctuating steam exit velocity as a function of frequency at said exit region;
and
obtaining a fluctuating pressure loading as a function of frequency on said component using said fluctuating steam exit velocity as a boundary condition for solving a 3-D Helmholtz equation in said steam dome to determine if said component can operate safely at said fluctuating pressure loading,
∇
2
⁢
P
-
1
a
2
⁢
∂
2
⁢
P
∂
2
⁢
t
=
0
,
and
wherein said 3-D Helmholtz equation is of the form
∇
2
⁢
P
+
ω
2
a
2
⁢
P
=
0
,
where P represents pressure, ω represents frequency, and a represents acoustic speed.

39 more elements

An apparatus for determining a fluctuating pressure loading on at least one component inside a reactor steam dome having at least one steam line for transferring steam away from said dome, said steam line being joined to said steam dome via an exit region and having at least one acoustic source therein, said apparatus comprising:

a computing device comprising a computer-readable medium comprising instructions for:
measuring pressure as a function of time at a first location in said steam line;
measuring pressure as a function of time at a second location in said steam line, wherein there is no said acoustic source between said first and second locations;
using said pressure measurements to calculate a fluctuating steam exit velocity as a function of frequency at said exit region;
and
obtaining a fluctuating pressure loading as a function of frequency on said component using said fluctuating steam exit velocity as a boundary condition for solving a 3-D Helmholtz equation in said steam dome to determine if said component can operate safely at said fluctuating pressure loading,
∇
2
⁢
P
-
1
a
2
⁢
∂
2
⁢
P
∂
2
⁢
t
=
0
,
and
wherein said 3-D Helmholtz equation is of the form
∇
2
⁢
P
+
ω
2
a
2
⁢
P
=
0
,
where P represents pressure, ω represents frequency, and a represents acoustic speed.

40 more elements

Dependencies are inferred from the claim text.

Description7,367 words

Summary886 words

#The present invention relates to the field of determining fluctuating pressure loading and more particularly, to determining fluctuating pressure loading on a component in a reactor steam dome.

#Boiling water nuclear reactors (BWR) have simple, robust designs and have been operating successfully in the US for many years. Based on this history of successful operation, many BWR operators want to extend the life of their reactors from the planned 35 years to 50 years and to increase the power from the reactors by about 15 to 20%. This increase in power may be obtained by simply increasing the rate of flow of steam, while keeping the total pressure in the system constant. This is possible because reactor power plants are designed to operate with the main control valves only 40% open. By opening the valves slightly more (to about 46-48% open) steam can be made to flow through the existing pipe system 15-20% faster, with no increase in the total pressure. As the power obtained from a steam turbine is proportional to the combination of steam density, which is directly proportional to pressure, and velocity, this will result in a corresponding increase in power output. Moreover, as there is no increase in total system pressure, the existing power station structure should not need to be changed in any fundamental way.

#The only significant uncertainty in making such a change is in predicting the changes in flow-induced vibrations that will result from the increased flow rate of the steam. The existing plants have a long history of operating at the present flow rates and dealing with the resultant flow-induced vibrations. Changing the rate of flow is going to change the vibrations, but exactly how they will change is not easy to predict or to measure.

Brief description of the drawings19 figures

#FIG. 1 is a drawing showing a schematic cross-section of a typical boiling water nuclear reactor (BWR).

#FIG. 2 is a schematic drawing showing an exemplary main steam line pipe geometry for a BWR.

#FIGS. 3A, 3B and 3C are schematic drawings showing three types of acoustic source in a typical piping system in a BWR nuclear power plant.

Detailed description6,088 words

#The present invention relates to systems and methods of determining fluctuating or unsteady pressure loads on a component within a reactor steam dome.

#To increase the power output from existing BWR nuclear power plants without structural changes, power plant operators would like to increase the velocity of the steam while keeping the total pressure of the system nearly the same. Although the total pressure of the system will not change, the increased steam velocity will change the fluctuating pressure loads on components, including components such as the steam dryers within the reactor steam dome. It is highly desirous to determine how these fluctuating pressures loads change so that appropriate strengthening of components can be made, if necessary.

#There are, however, fundamental difficulties in predicting how fluctuating pressures will change with changes in steam velocity. Furthermore, the hostile, radioactive environment within the steam dome makes direct measurement of the vibrations on components very expensive and difficult.

Facts

Application

11/135,806Filed 24 May 2005 · us provisional application

Priority

25 May 2004

Published

US 2006/0078081 A113 Apr 2006

Granted

28 Oct 2008

Term ended

3 Aug 2025

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 71 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification7 codes

G21C 17/00
Monitoring
G21D 3/001
Control of nuclear power plant: computer implemented control
Y02E 30/00
Energy generation of nuclear origin
Y02E 30/30
Energy generation of nuclear origin: nuclear fission reactors

Timeline

25 May 2004Priority claimedParent application 60/573,844
24 May 2005Application filedUS 11/135,806
24 May 2005Assigned to Continuum Dynamics, Inc.assignment of assignor's interest
7 Nov 2005Assigned to Continuum Dynamics, Inc.assignment of assignor's interest
13 Apr 2006PublishedUS 2006/0078081 A1
16 Nov 2007Assigned to Continuum Dynamics, Inc.assignment of assignor's interest
11 Feb 2008Assigned to Westinghouse Electric Company LLCassignment of assignor's interest
28 Oct 2008GrantedUS 7,444,246 B2
1 Aug 2018Assigned to Credit Suisse AG, Cayman Islands Branch, AS Collateral Agentsecurity interest
1 Aug 2018Assigned to Goldman Sachs Bank USA, AS Collateral Agentsecurity interest
1 Aug 2018Assigned to Bank of Montreal, AS Administrative Agentsecurity interest
1 Aug 2019Assigned to Westinghouse Electric Company LLC, Fauske and Associates LLCrelease of security interest in patents
27 May 2022Assigned to Bank of Montreal, AS Collateral Agentpatent security agreement
26 Jan 2024Assigned to Deutsche Bank AG New York Branch, AS Collateral Agentsecurity interest
30 Jan 2024Assigned to Westinghouse Electric Company LLC, Fauske and Associates LLCrelease of security interest in patents
30 Jan 2024Assigned to Westinghouse Electric Company LLC, Bhi Energy I Specialty Services LLCrelease of security interest in patents
3 Aug 2025Term endedEstimated, includes 71 days of adjustment

System and method for determining fluctuating pressure loading on a component in a reactor steam dome

Life of this patent

System and method for determining fluctuating pressure loading on a component in a reactor steam dome

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims41

Description7,367 words

Drawings

Classification7 codes

Life of this patent

Description7,367 words