Nuclear Filtration, LLC
APPARATUS FOR RADIOACTIVE PARTICULATE FILTRATION
MARKETING INFORMATION PAPER

There are currently in excess of one-hundred (100) light water reactor nuclear power plants operating within the United States; and many others in foreign countries. Radioactive corrosion products are present in varying accumulations throughout all light water reactor plants. The radioactive corrosion products/deposits are commonly referred to as “CRUD” an acronym for Clinch River Unidentified Deposits, a term coined to describe the usually black or gray, highly radioactive deposits that were first noted in the very early experimental light water reactor plants; most notable at the Clinch River facility.

Radiation emanating from CRUD deposits is the primary source of occupational radiation exposure in a typical nuclear power plant. NRC regulations continually reduce the allowable radiation exposure dose to all personnel within each station, which forces the utilities to find more effective ways to deal with it.

CRUD accumulates inside the piping systems, fuel pools, fuel transfer canals, and all other areas that communicate hydraulically with the reactor coolant systems. It is deposited on the inside of the piping walls, on the bottom and sidewalls of the fuel pools, inside valve bodies and instruments, and on the surfaces of everything coming into contact with the contaminated water. The CRUD particles entrained in leaked or spoiled radioactive water must be thoroughly cleaned up immediately to prevent them from being tracked throughout the plant; or worse, from drying out and going airborne and contaminating the air within the plant. Once airborne, the CRUD contaminates everything the air contacts; walls, ceilings, piping, light fixtures, cables, equipment surfaces, and the respiratory system of personnel breathing the contaminated air. CRUD will become a VERY serious problem at some point in the life of every light water reactor plant.

The presence of CRUD inside the station piping system drives up the cost of routine operations and maintenance of the plant many fold. Simple, inexpensive tasks become highly intricate and inordinately expensive because of the extreme methods that must be employed to cope with the radioactivity emanating from the CRUD, and to prevent the release of CRUD to the stations environs.

Current filtration technology can remove the CRUD from the station fluid systems; however, collection of significant quantities of CRUD in conventional filters creates major radiological problems in removing the spent cartridges. The radiological penalties associated with cartridge change-out are nearly as bad as those associated with leaving the CRUD in place, inside the fluid system.

The radiological problems associated with cartridge change-out have been so troublesome that they have severely limited the use of cartridge filtration technology in commercial nuclear power plants. Finding a way to remove CRUD from troublesome areas without creating additional radiological problems in the process would be viewed as a noble effort, indeed. That is precisely what the new APPARATUS FOR RADIOACTIVE PARTICULATE FILTRATION filter/cartridge change-out system does. It will allow unimpeded utilization of the unique filtration technology without the severe radiological penalties associated with current cartridge change-out systems.

Nuclear Filtration LLC has produced an animation of the system that shows the complete filtration system set-up including the filtration process, indexing of the filters, filter removal, clean filter replacement, dirty filter packaging and removal.  Here in the narrative form we will explain the process in detail as follows:

  1. The process begins with cooling water contaminated with CRUD entering the filtration vessel thru a distribution block at the top of the filtration vessel.  It is important to note at this time that the CRUD contaminated water flows from the inside to the outside of the filter element.  This direction of flow captures the CRUD particles within the contaminated water inside the filter element allowing only clean filtered water to enter the main chamber of the filtration vessel.  The primary advantage of this type of filtration flow is that the interior of the vessel, outside of the filters, remains clean and free of contaminated CRUD particulate matter.

  2. Our patented process of filter change-out allows us to remove the dirty filter cartridges without having to disassemble the vessel for cleaning.  This in turn will significantly reduce personnel exposure as well as overall filter change out time.

  3. The filter change-out process will begin once the filters have reached their facility’s pre-set administrative limit for contamination as defined by particulate loading and/or contamination levels.  The process begins by isolating the liquid flow to and from the filtration vessel. After isolation has been completed the vessel will be vented and drained. The filter carrier now containing clean filter cartridges will be positioned under the filter change-out valve. Once the carrier is positioned the indexing valve is opened. The basket indexing tool will be inserted through the upper floor penetration and indexing valve into the seal shaft, once engaged into the seal shaft the entire unit, including the seal shaft, is withdrawn to allow for a complete visual inspection of seals.  The basket indexing tool is once again inserted through the upper floor penetration and engaged into the basket port shaft assembly. After the basket indexing tool is engaged the basket is indexed 22.5° to align the first contaminated filter with the change-out nozzle.  The upper and lower filter change-out valves are then opened.  Once all appropriate valves are opened the filter change-out tool is inserted through the upper floor penetration and upper change out nozzle and engaged into the filter adaptor.  Once engaged the filter change-out tool is used to push the contaminated filter cartridge out of the vessel and into the first empty position in the filter carrier. Then the filter change-out tool is retracted back into the vessel thus allowing the filter carrier to be indexed to the first clean filter cartridge in the filter carrier. Once the filter carrier is positioned the filter change-out tool is pushed into the filter adaptor atop the clean filter cartridge and engaged.  The clean filter cartridge assembly is then extracted from the carrier and into the vessel where it is engaged into the filter socket.  Once engaged the filter change-out tool is retracted and the basket assembly is rotated 45°.  This completes the change-out for one filter. This process is then repeated for the additional seven filters.  Please Note:  In the animation is a cut away view of the filter showing the CRUD being caught on the inside of the filter.

  4. After the completion of the change-out of all eight filters the filter change-out valves are closed, and then the basket assembly is rotated 22.5° to lock the filter assembly into operating position.  The basket indexing tool is retracted and the seal shaft is re-inserted into the vessel.  The basket indexing tool is removed from the vessel and stored.  Then the valves for the filtration vessel drain and basket indexing tool are closed.  The unit is now ready to be activated and returned to service.

  5. The start-up procedure will include filling and pressurizing the vessel.  Upon final pressurization the system will be placed into normal operating service.

In summary Nuclear Filtration’s patented Apparatus for Radioactive Particulate Filtration change-out system has the following advantages:

  • Reduced personnel exposure on which EPRI has placed a $10,000 per REM cost.  This reduced exposure is not only due to the ease with which filters can be changed but also due to the reduced exposure allowed by maintaining cleaner cooling water throughout the plant thus reducing overall exposure.
  • Reduced outage time for filter change out due to modern technology.  This is demonstrated by the spreadsheets shown below of a comparison of existing technology with the Apparatus for Radioactive Particulate Filtration.
WORK INSTRUCTION SUMMARY
TYPICAL LIGHT WATER REACTOR
CURRENT FILTRATION TECHNOLOGY
         
    Persons Hours Hours
Step Description Req. Person Operation
         
1 Preparation & Health Physics 1 0.60 0.60
2 Last Performance Notes 4 0.50 2.00
3 Prefabrication Venting Aids 1 5.00 5.00
4 Foreign Material Exclusion 1 0.10 0.10
5 Accept Clearance 1 0.10 0.10
6 Install Scaffold & Shielding 3 4.00 12.00
7 Install Ventilation Aid 2 2.00 4.00
8 Vent Filter 1 1.00 1.00
9 Remove Elements 8 6.00 48.00
10 Drain Filter Housing 1 3.00 3.00
11 Decon Filter Housing 2 3.00 6.00
12 Install New Filter Elements & Vent Valve 5 7.00 35.00
13 Release Clearance 1 0.10 0.10
14 Post Maintenance Test 1 1.00 1.00
15 Remove Shielding 3 2.00 6.00
         
      Total Hours for Change-Out
 		 123.90

 

 

 

 

 
NUCLEAR FILTRATION LLC
APPARATUS FOR RADIOACTIVE PARTICULATE FILTRATION
         
    Persons Hours Hours
Step Description Req. Person Operation
         
1 Preparation & Health Physics 1 0.60 0.60
2 Last Performance Notes 4 0.50 2.00
3 Prefabrication Venting Aids 0 0.00 0.00
4 Foreign Material Exclusion 1 0.10 0.10
5 Accept Clearance 1 0.10 0.10
6 Install Scaffold & Shielding 0 0.00 0.00
7 Install Ventilation Aid 0 0.00 0.00
8 Vent Filter 0 0.00 0.00
9 Remove Elements 1 0.33 0.33
10 Drain Filter Housing 0 0.00 0.00
11 Decon Filter Housing 0 0.00 0.00
12 Install New Filter Elements & Vent Valve 1 0.33 0.33
13 Release Clearance 1 0.10 0.10
14 Post Maintenance Test 1 1.00 1.00
15 Remove Shielding 0 0.00 0.00
         
      Total Hours for Change Out 4.58
         
  • No vessel disassembly required to change out the filters.  This not only reduces exposure and saves money and time but also allows, indeed encourages the use of the recommended smaller sub-micron filters which have been shown to improve water chemistry due to the ease of change-out which will be more frequent with the sub micron filters.
  • Significant dollar savings will be gained in many places thru-out the plant via the use of modern technology providing a more operator friendly system which creates a friendlier overall environment.
  • Modular design allows easy retrofit and start-up in existing nuclear facilities.
  • Minimal start-up costs.
  • Reduced outage time due to being able to change out the filters is less time as well as possibly having the ability of extending the Primary System Chemical De-Con cycle by 1-5 years utilizing this technology.  The spreadsheet below shows the savings that are likely possible by extending the cycle time of the Primary System Chemical De-Con.
PRIMARY SYSTEM CHEMICAL DECON
PERFORMED APPROXIMATELY ONCE EVERY TEN YEARS
CALCULATED IN 2008 DOLLARS
       
Description Cost/Occurrence    
       
Chemical De-Con $160,000,000    
30 Day Power Outage $108,000,000    
       
Total Cost/Occurrence $268,000,000    
       
    Savings per Year if Cycle
If Amortized Over Cost/Year is Extended
       
10 Years $26,800,000    
11 Years $24,363,636 $2,436,364
12 Years $22,333,333 $4,466,667
13 Years $20,615,385 $6,184,615
14 Years $19,142,857 $7,657,143
15 Years $17,866,667 $8,933,333
       
       
  • Better filtration levels achieved through the use of sub-micron filter elements that can now be considered due to the ease of more frequent change-outs made easy by the Apparatus for Radioactive Particulate Filtration.  Lower CRUD equals improved reactor efficiencies as indicated by EPRI in a recently published study. This can cause a very dramatic increase in income as is illustrated in the spreadsheet below.
NUCLEAR POWER GENERATION
OVERALL PLANT EFFICIENCY
       
    Standard Efficiency
Plant Size Price/kWh Yearly Sales
2,000 Megawatts $0.0750 $1,314,000,000
       
% of Increased Efficiency Increase in Yearly Sales
1% $13,140,000
2% $26,280,000
3% $39,420,000
4% $52,560,000
5% $65,700,000

There are many applications in a typical nuclear plant where use of the new filtration system would result in dramatic reduction of background radiation levels and specific worker dose accumulation associated with many critical tasks. Once the dose reduction effects made practical by the new APPARATUS FOR RADIOACTIVE PARTICULATE FILTRATION system have been demonstrated, there is no doubt that numerous applications will easily be identifiable at any commercial light water reactor, involving radioactive fluids.

One of the target areas for introduction of the new APPARATUS FOR RADIOACTIVE PARTICULATE FILTRATION is temporary installation adjacent to spent fuel storage pools and other locations where radioactive CRUD deposits are creating unacceptably high background radiation levels.

This application is ideal for minimizing startup costs because in most cases it will not require changes to the stations permanent piping systems. It is also an ideal application to showcase the unique radiological advantages offered by the unit’s cartridge change-out system; because the filter cartridges will become highly radioactive and significant area dose reduction will result. Efforts to remove the CRUD with existing filtration system have historically resulted in extremely high radiation dose to those involved in the operation, and inordinately high cleanup costs associated with the spillage of radioactively contaminated fluids during the cartridge change-out process. The new APPARATUS FOR RADIOACTIVE PARTICULATE FILTRATION system will essentially eliminate both of these problems.

235 Beaver Drive
P.O. Box 527A
Du Bois, PA 15801

(814) 372-1500 Phone
(814) 375-0718 Fax
draybuck@nuclearfiltration.com
www.nuclearfiltration.com

Nuclear Filtration LLC was established in early 2008 to market equipment to the nuclear industry under United States Patent # 6,254,774 which applies to the Apparatus for Radioactive Particulate Filtration covered by this Patent. The Patent was issued on July 3, 2001.