PWR Dispersant Review & UpdateOptiSperse PWR6600

July 1, 2010

Tony Rossi

Global Boiler Water

Product Manager

GE Water and Process

Technologies

Trevose, PA

anthony.rossi@ge.com

2 /GE /

OptiSperse PWR6600

Performance Goals & Development History

PWR –> Pressurized Water Reactor

We will specifically discuss the application of a polymeric dispersant

for control of iron oxide deposition in the

“secondary-side” steam generators which receive

as the heat source radioactive primary water

from the reactor core, and utilize the thermal energy to product 900 to

1000 psig saturated steam for power generation in traditional

steam turbines. The units to which the dispersant is applicable on-line

are recirculating PWR designs with continuous blowdown,

versus once-through SG designs. Typical recirculating PWR designs

include a set of 2 to 4 Steam Generators producing approximately 800 to 1200

Megawatts of electrical power at peak capacity, and generating between

1.2 and 1.6 billion pounds of steam per hour.

3 /GE /

Pressurized Water Reactor (PWR)Schematic

4 /GE /

OptiSperse PWR6600Dispersant Development

• Joint development effort – CommEd (now Exelon) and BetzDearborn (now GE Water) –> 3 active patents

• Unique, high molecular weight polyacrylate with high-purityorganic initiators – no sulfates, chlorides

•More than an order of magnitude higher in MW of typical synthetic polymers used in fossil boiler applications

• Laboratory testing showed surprisingly high iron oxide dispersion activity at very low Polyacrylate (PAA) dosages

• At SG pressure of 900 psig, dispersant is well within normal pressure range of fossil boilers

• EPRI – Electric Power Research Institute – Has managed, evaluated and monitored the process to trial and qualify

the dispersant since 2000 ->

– Dr. Keith Fruzzetti – EPRI Nuclear Chemistry Program Manager

5 /GE /

Goals of PWR Dispersant Application in PWRs

o Sustainable, long-term reduction of iron corrosion product accumulation in SG of 50% or greater

o Current level of accumulation of iron corrosion product is > 95%

o Reduced potential for corrosion under deposits in occluded areas

o Reduced possibility of thermohydraulic instabilities caused by blockage of tube supports

o Long-term SG thermal performance benefit o Improved heat transfer efficiency and thermal margin

o Potential for long-term reduction in routine off-line cleaning frequency-> sludge lancing

o Long-term goal is reduction in frequency or complete avoidance of full bundle steam generator chemical cleaning procedures

o Negligible or easily-managed secondary effects on operations, SGand BOP materials

6 /GE /

EPRI Evaluation Project

Short Term Trial Results

Arkansas Nuclear ANO-2

7 /GE /

Short-Term Trial- ANO 2- Spring 2000Key Performance Summary

• Heavily fouled Westinghouse 1st generation Steam generator (SG)

• Iron rejection to SG blowdown increased from 1-2% (negligible) to 20 –60% with 0.5 to 12 ppb active PAA dispersant fed to the SG feedwater

• Small but measurable increase in global fouling factor (14 uh-ft2-0F/BTU) at elevated PAA feedrate of 6 – 12 ppb

• No measurable effect on FF at feedrates up to 4 ppb PAA

• No changes in cation conductivity were observed

• No impact on ion exchange resins

• Performance met pre-trial goals, except for small increase in measured fouling factor at elevated PAA feedrate

8 /GE /

EPRI Evaluation Project

PWR Dispersant

Long Term Trial Results

9 /GE /

Long-Term Trial – Duke McGuire 2Aug. 2005 – Aug. 2007

• At 1.5 to 4 ppb active PAA feedrate, steady-state iron rejection to blowdown increased from < 5% to 45 – 50% - See Fig 1

• Initial injection removed large quantity of easily dispersed iron – see Fig 2

– Lesson - Blowdown filter management at outset

• Approx. 200 lbs total iron removed from Aug 2005 > June 2006 - Fig 3

• Small but measurable effect on cation conductivity + 0.15 uS/cm

– Amine chemistry is major CC contributor – Range 0.2 – 1 uS/cm

• Change is steam flow indications- Attributed to defouling of secondary steam separators/outlet venturis- Caused no operational issues as steam flow measurement not used

• Slight fouling factor decrease - 4 uh-ft2-0F/BTU- Opposite the effect observed at ANO-2 STT

10 /GE /

Figure 2 - McGuire Unit 2 IronChronological history of PAA trial

FW Iron/Blowdown Iron/FW PAA concentrations vs. time

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11 /GE /

Figure 3 - McGuire Unit 2 Progressive Total Pounds of Iron Removed

Aug 2005 through June 2006

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12 /GE /

Long-Term Trial – Duke McGuire 2Key Experiences & Learning

PAA performed effectively and reproducibly as iron dispersant

o 2 – 4 ppb PAA in Boiler feedwater effective for average of 1 – 2 ppb FW Fe

o 45 – 50% rejection of FW iron to SG blowdown (vs. < 5% without disp.)

o Plant-specific optimization of PAA:Fe stoichiometry

Effect on cycle chemistry is manageable- Dispersant addition became routine

Changes in steam flow indications due to defouling of moisture separators

13 /GE /

EPRI Qualification & Application

14 /GE /

EPRI Dispersant Qualification and Application Guidelines Development

• Dispersant Guidelines and Application Sourcebook published– Dec 2007 – EPRI Publication 1015020

– The Dispersant Sourcebook provide comprehensive application and monitoring guidance

• Dispersant included as approved chemistry for management of iron oxide accumulation in recirculating PWR Steam Generators in 2009 revision of EPRI PWR Secondary Steam Generator Chemistry Guidelines

• INPO credits dispersant use by reducing the CEI iron termfor those applying dispersant– INPO – Institute of Nuclear Power Operations

15 /GE /

2010 Exelon Dispersant Application

Update

Update

16 /GE /

Exelon Byron 1 Dispersant Application Update

Byron 1 initiated PWR6600 feed in April 2009. Results through May 2010:

- Significant rejection of existing iron inventory at 1 ppb PAA in feedwater > 100% iron rejection initially

– Sustained rejection of BFW iron to blowdown of greater than 50% (increased from pre-PAA iron transport < 5%)

– Enhanced thermal performance

Indicated steam flow values returning to “new steamgenerator performance

Main steam pressure increase –> Increased power output potential

Positive impact on thermal margin –> Valve Wide Open (VWO) margin has increased significantly –> 7% valve travel orapprox. 1% increased steam flow margin

17 /GE /

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Exelon Byron 1 PWR Dispersant Spring 2010 Update Steam Generator Blowdown Iron Concentration

Application period: March 2009 -> April 2010

18 /GE /

Exelon Byron 1 – Main Steam Pressure Increasewith PWR Dispersant Feed

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19 /GE /

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Exelon Byron 1#4 Steam Governor Valve Position versus VWO with

PWR Dispersant Feed

20 /GE /

Exelon Braidwood/TMI Application Updates

• PWR6600 injection initiated at Braidwood 1 in January 2010– Results through May2010 very similar to Bryon 1

• Three Mile Island (TMI) Off-line Soak Dispersant application– OptiSperse PWR6600 increased iron removal from PWR once-through

steam generator when added as off-line soak/wet lay-up additive

• EPRI-sponsored “long-path recirculation” condensate flushdemonstration scheduled for Spring 2011 at Exelon Byron PWR

21 /GE /

This Session is now

Open for Questions

Thank You