jet pump flow control collar - amazon s3 · new slip joint clamp not addressing major contributor...

Jet PumpFlow Control Collar

Wade MarkhamProduct Manager

Background

Background

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GE BWR/3-6Core Flow by: Recirculation Pumps and Jet Pumps

Safety Design Basis Assures 2/3 core coverage post

accident LPCI flow path

BWR Recirculation SystemEPRI 2016 Conference - Jet Pump Flow Control Collar

BWR Slip Joint GeometryHold Down Beam

Inlet mixer

Diffuser

Restrainer Bracket

Slip joint

Riser Brace

Riser Pipe

Slip Joint Section View

Mixer Assembly

Jet Pump Assembly

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Existing Configuration has a Long Annular Flow Path which makes the Slip Joint Unstable

EPRI 2016 Conference - Jet Pump Flow Control Collar

Causes of Flow Induced Vibration

Leakage is the largest contributor to vibration in the jet pump Numerous evaluations have confirmed

EPRI Moss Landing Tests Argonne National Labs

Leakage can be outward or inward based on flow in the jet pump

Vane passing frequencies from recirculation pumps Resonate with natural frequencies of the jet

pump

Turbulent flow from the mixer nozzles

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Slip Joint FIV is the Major ContributorEPRI 2016 Conference - Jet Pump Flow Control Collar

Specific Issues

Labyrinth Seal Repair

Pro-Active Steps May Have Worsened Issue 7EPRI 2016 Conference - Jet Pump Flow Control Collar

Lab seal reduces leakage - does not make flow path stableExcessive wear on Labyrinth Seal in the slip jointSlip joint gaps approach .10” Originally .010”

Original Condition

Auxiliary Wedge & Oversize Wedge Repair Methods

Auxiliary wedges damage set screws and mixer After one cycle of operation

Oversize wedge vibration wears guide rod After one cycle of operation

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Wedges Do Not Address Vibration Source


Slip Joint ClampsAfter one cycle, excessive vibration has cut into diffuser over .25”Jack screw has cut into diffuserThermal cycle on slip joint clamps will allow to loosen over time

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New Slip Joint Clamp Not Addressing Major Contributor


AREVA SolutionDesign Features and Interface Geometry

Design / Performance Requirements

Block as much leakage as possible M-ratio 1.85 design (2.20 actual) (Ratio of output flow vs input) Core Flow 108Mlb/hr 5.4Mlb/hr per jet pump ~10.8k gpm 4.9k gpm from

recirc pump. Core plate DP = ~17 psi Limit leakage below initial design (Initial design gap of slip joint is .010” on

diameter) Operating temperature ~618F

Allow for thermal growth between the mixer and the diffuser .09” of thermal growth expected at slip joint assembly

Avoid any modifications to existing hardwareDesign for remote installationDesign to prevent FME (minimize parts)

11EPRI 2016 Conference - Jet Pump Flow Control Collar

Design RequirementsCodes & Standards Non-code BWRVIP-84 Materials BWRVIP-41 BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines BWRVIP-51-A Jet Pump Repair Design Criteria

Loads Repair would be evaluated based on a comparative analysis evaluation If Section III analysis is requested then Jet pump load data will be required.

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Our Design Seals, Restrains, and Meets BWRVIP Requirements


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Only Design that Provides Sealing and RestraintEPRI 2016 Conference - Jet Pump Flow Control Collar

Mixer Seal

Hinged joint

Swing clamps to engage diffuser fins

Full contact (clamp does not engage on mixer)

Relief for diffuser fin~34 lbs

Diffuser Seal

Flow Control CollarDesign Features

Flow Control CollarFME Features

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Eliminates Potential for FMEEPRI 2016 Conference - Jet Pump Flow Control Collar

Hinge pin capture feature

Swing clamp capture feature

Captured fastener

Standard crimp cup on shoulder screws

AREVA Flow Control Collar Advantages

The optimal solution that addresses the largest contributor of FIV OEM Aux Wedges and Slip Joint Clamps do not fix the

problem

Minimizes potential leak paths to restrict flowProvides lateral support to tie the mixer to the diffuser while allowing thermal growth Replaces the function of the Slip Joint Clamp

Simple installation, without jet pump disassemblyMinimizes the number of parts in the repair hardwareDoes not require modification to existing hardwareRepair for Life-of-Plant

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Optimal Solution for Jet Pump Repair


Measurements to Validate Mixer Geometry

Insufficient Detail on Original Drawings Performed measurements at Susquehanna in Spring 2014

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As-Built Dimensions Recorded


Jet Pump Sealing FeaturesO-ring seal design compliant to mixer diameter Dovetail groove used to capture O-ring

segment to collar body

Mixer diameters previously confirmed with as-built measurements As measured ranges from 10.011 –

10.060 Design diameter 10.04 +/- .06

Lower seal to diffuser Compression of seal in counterbore Conforms to existing geometry

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Our Design Addresses All Normal Leak PathsEPRI 2016 Conference - Jet Pump Flow Control Collar

Swing ClampsShoulder screw thru collar body Must handle axial and bending loads from

preload as well as axial load from thermal growth

Swing clamps can be locked (tightened) in position when delivered to jet pump Clamp must be positioned before installation

to clear riser pipe and eliminate interference issues

Retainer on swing clamp eliminates potential for FMESwing Clamps threaded in right hand and left hand versions Provides restraint similar to slip joint clamp

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Innovative Engagement Mechanism


O-Ring SealRequires ~200psi to reach yield strength ~625 lbs of compression force

exerted on mixer

Results in resistance to thermal growth of ~440 lbsThis load must be resisted with the swing clampsO-ring must be able to withstand ~100 thermal cycles / Axial motions without failure (wear thru wall)Qualification of O-ring wear will be performed to validate life

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O-Ring Seals while Allowing Thermal Growth


Analysis of the Repair

Analysis will be performed to determine a relative motion between the mixer and diffuserHolding force vs. time/temperature will be calculated, to assess primary qualification and to do fatigue calculation Loads on the mixer and diffuser will be evaluated (expected to be negligible)


AREVA Teams with Structural Integrity Associates, Inc.

Comprehensive repair solutions to ensure operational excellence in the U.S. boiling water reactor (BWR) fleet: Onsite and offsite engineering analysis Repair, and replacement of BWR vessel internals

Repair and replacement capabilities, including but not limited to the following components: Jet Pumps Feedwater Spargers Core Spray Piping Core Shroud Top Guide Core Plate Reactor Vessel Steam Dryer Steam Separator

Benefits: AREVA has extensive experience in BWR internals

repair and replacement SI has a highly respected and proven reputation as a

quality provider of reliable BWR engineering analysis One integrated source for cost-effective BWR

analysis and repair solutions Service providers that know your teams and

understand your cultureBest of the Best for Engineering &

Installation ServicesEPRI 2016 Conference - Jet Pump Flow Control Collar 21

Preliminary Testing Results

Completed Mockup Testing

Completed Test Plan Perform initial visual inspections Perform baseline flow test (No FCC) Perform baseline vibration (No FCC) Install FCC & perform initial flow test Simulate thermal cycling

Axial actuation over 100 times Simulates life of plant

Repeat flow test Apply Vibration loads

~3 million cycles 150 hz for 6 hours 500 lb force 1-2G accelerations

Repeat flow test Perform as left visual inspections Repeat for additional seal configurations

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POP Tests Simulate Jet Pump ConditionsEPRI 2016 Conference - Jet Pump Flow Control Collar

Completed Mockup Testing

Mockup designed to simulate jet pump in “excited” condition Mechanical agitation used to simulate FIV

Testing includes more vibration “runtime” than EPRI facility with standard test program Majority of test time at EPRI facility is for establishing the

parameter to create the vibration Once established the repair is cycled thru the conditions and

monitored for response AREVA testing allows instant excitation so that the repair is

ensured to be responding to a worst case condition Extended run times in the excited state may be performed

without the expense and uncertainty in the EPRI facility

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Good Results under Exaggerated Plant ConditionsEPRI 2016 Conference - Jet Pump Flow Control Collar

Test FixtureAxial & Flow Test Mode

Hydraulic Cylinder Provides axial motion to

simulate thermal growth ~.2” travel

Pump Connections Connects to submersible

pumps 2 hp & 5 hp pumps capable of

over 100 gpm

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Hydraulic Cylinder

Pump Connection

Slip JointRegion

Restrainer Bracket

Axial Motion from Thermal Growth hadNo Effects on FCC Function


Test FixtureVibration Mode

Slip joint 1/16” diametrical clearance

Restrainer Bracket Spaced to match

Susquehanna above slip joint Acts as pivot point for motion

at the slip joint

Vibration Source 500 lbs of force 150 hz (9000 RPM) Regulated with Variac ~ 2g Acceleration

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Electric Vibration Source

Restrainer Bracket(Pivot)

Slip JointWith FCC

Accelerometer Mounting tab

Mockup to replicate Vibration of “Excited” Jet Pump


Seal Materials

Three seals evaluated for the test Stainless Steel O-Ring

Materials readily available Need to improve fabrication method

Grafoil seal Already used in plant for many sealing applications Rated for 2030 psi Rated for 896 F

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AREVA has confirmed two options for seal materialsEPRI 2016 Conference - Jet Pump Flow Control Collar

Vibration ResultsVideo of Vibration

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With SS O-Ring

Baseline

With Grafoil

Dramatic Decrease in Vibration


Flow ResultsCondition Pressure Leakage Flowrate Observations

Without FCC – initial 7.5 psi (max achievable) 131 GPM All flow channeled thru slip joint exceeded ability of pumps to reach 20 psi.

Without FCC – Calculated values 20 psi (estimated) 433 GPM (estimated)

With FCC – SS O-Ring -initial 20 psi 20 GPM Minor leakage observed around seal spraying vertically upward and horizontally around base

With FCC – – SS O-Ring -after axial cycles (>100 cycles)

20 psi 20 GPM

With FCC – – SS O-Ring -After 6 hours at 150hz and 1-2 g accel.

20 psi 25 GPM

With FCC – Grafoil - initial 20 psi 6 GPM Almost all vertical leakage arrested. Majority of leakage from base of FCC

With FCC – – Grafoil - after axial cycles (>100 cycles)

20 psi 6 GPM

With FCC – – Grafoil - After 4 hours at 150hz and 1-2 g accel.

20 psi 6 GPM

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Both Seals are effectiveEPRI 2016 Conference - Jet Pump Flow Control Collar

Wear Results

No wear observedDiscoloration noted Removed with cleaning

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Before Testing After Testing

Before Testing After Testing

No Wear Observed


Discoloration -No Wear

No Wear

Additional Proposed Testing

Final seal design qualification testing Perform extensive vibration testing on final seal design Validate longevity of seal design

Extended run time vibration testing

Crimp cup qualification testing Confirm breakaway torque for removal of crimped fasteners Confirm crimp engagement parameters

EPRI 2016 Conference - Jet Pump Flow Control Collar 31

Planning Success without EPRI Testing

Conclusions and Observations

The Flow Control Collar reduces leakage and resists vibrationThe SS O-ring could be improved by: Annealing the O-ring Better forming to avoid ovalization Thinner wall thickness Silver coating similar to head o-rings

Grafoil packing performed very well Verifying life of grafoil seal material under vibration loading with manufacturer

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Testing Confirms Flow Control Collar Reduces Leakage and Resists Vibration


Feature Comparison

EPRI 2016 Conference - Jet Pump Flow Control Collar 33

Feature AREVA FCC

Slip Joint Clamp

AuxilliaryWedge

AVS 1

The FCC is the clear choice

Restricts Leakage

Provides Lateral Support at Slip Joint

Does Not Require Modification to Existing Components

Prevents Flow Induced Vibration

Returns jet pump to full function

One DirectionAt Restrainer BRKT

At Restrainer BRKT

Installation

Flow Control CollarInstallation Clearances

Collar geometry has room for installation with additional space for toolingClearance by Restrainer bracket

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Adequate Room for installationEPRI 2016 Conference - Jet Pump Flow Control Collar


Collar will be opened and engage mixer assembly under restrainer bracket



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Installed Collars do not interfere with adjacent collar installation


Why AREVA

Most effective solution to Seal and Restrain the jet pump slip joint Minimizes potential leak paths to restrict flow Provides lateral support to tie the mixer to the

diffuser while allowing thermal growth Replaces the function of the Slip Joint Clamp

Simple installation, without jet pump disassemblyDoes not require modification to existing hardwareRepair for Life-of-PlantAREVA is ready to work with Utilities to resolve your jet pump issues


jet pump flow control collar - amazon s3 · new slip joint clamp not addressing major contributor...

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