ML20140E253

Rev 0 to Summary Rept of Performance of Performance Contracting Incs Sure-Flow Suction Strainer W/Various Mixes of Simulated Post-LOCA Debris

ML20140E253
Person / Time
Site:	Brunswick
Issue date:	02/14/1997
From:	Hart G PERFORMANCE CONTRACTING, INC.
To:
Shared Package
ML20140E210	List: BSEP-97-0209, Forwards Addl Plant Specific Info to Support Review of Proposed Strainer Replacements,In Response to NRC Bulletin 96-003, Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Bwrs ML20140E243 ML20140E253
References
NUDOCS 9706110289
Download: ML20140E253 (29)

Text

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-. n P:dPC PERFORMANCE CONTRACTING INC 4025 Bonner Industrial Drive, Shawnn, Konsos 66226 j

iscistIato sysitMs mssom Telephone: 913 4410100 Fax: 913 4410953 Summary Report on Performance of 1

Performance Contracting, Inc.'s Sure-Flow

• Suction Strainer with Various Mixes of Simulated Post-LOCA Debris Revision 0 Written by Gordon H. Hart, P.E.

February 14,1997 l

PROFORMANCE

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Summ:;ry Report c3 th2 Perf:rm nce cf Perf:rmscca Centracting, Inc.'s Sure-Fisw" Suction Strcir:r with Vari:us Mixes cf Simul:ted post-LOCA Debris, Rev.0 02/14/97 l

l TABLE OF CONTENTS l

Page No.

Su m ma ry of the Performa ace Evaluation................................................

1 1

I L Description of the Tested Sure-Flow Strainer Prototype........................ 2 H. Description of the Test Facility......................................................... 3 IB. T es t R es u lts................................................................................ 6 A. Ha re Strainer Head Loss........................................................ 6 B. Strainer Head Loss with Simulated Debris................................10 1

C. A ppa rent Filtration Efficiency................................................15 D. Fib ro us Bed Co m paction....................................................... 15 IV. Regression Analysis of Test Data................................................... 16 V.

Theoretical Analysis of Strainer Behavior......................................... 21 VL Co n cl us io ns.............................................................................. 2 6 O

e

Summ:ry Report c2 tha Perf2rm uee cf Parf rmines Centractirg,Inc.'s Sure -

Fl w S:ction Strair:r with Vctis:s Mixes cf Simul:ted post-LOCA Debris, Rev.0 02/14/97

SUMMARY

OF THE PERFORMANCE EVALUATION The Sure-Flow

• Suction Strainer has been designed and developed specifically for attachment to the Emergency Core Cooling System lines on Boiling Water Reactor nuclear plants. The strainer is intended to reduce the post-LOCA Head Loss across the entrance to the ECCS line with the purpose of maintaining ECCS pump flow at the design value. To accomplish this, these strainers are also designed to be install:d on the i

l ends of the ECCS lines, in the suppression pool and upstream of the ECCS pumps. High performance strainers such as these have been determined to be necessary on BWR l

plants because it has been found that the collection of LOCA generated debris and other materials can casily bloc!r. e.visting small, passive strainers. The Sure-Flow Strainers can alleviate that problem and thereby keep water flow at design values through the ECCS lines.

To evaluate the Sure-Flow Strainer's performance, a prototype was fabricated by PCI l

and tested at the Electric Power Research Institute by the US Boiling Water Reactor Owners' Group in December,1995 as part of their strainer testing program (Ref.1).

Those tests used shredded NUKON* fiberglass insulation to simulate post-LOCA fibrous debris and they used iron oxide particulate to simulate suppression pool sludge.

However, in these 1995 tests, the quantities of fibrous debris were limited to relatively low quantities. Therefore, to evaluate the performance of this strainer with larger quantities of fibrous debris, additional tests were conducted at EPRI in October,1996. In addition, one additional test was conducted with stainless steel foil, shredded to simulate i

foil debris from Reflective Metallic Insulation (RMI), and then combined with fibrous debris and particulate.

l Combined, these two sets of Head Loss performance tests showed the following behavior of the Sure-Flow Strainer prototype with this debris mixture:

The bare strainer (i.e., with no debris) showed a very low Head Loss behavior and that Head Loss is linearly dependent on the square of the entrance (i.e., at the strainer's nozzle) water velocity.

its Head Loss behavior is essentially linearly dependent on both Mass of Fibrous e

Debris and Water Flow Rate, the addition of 100 lbs. of CP particulate increases Head Loss across the strainer by e

about 60%,

. the Head Loss behavior can be accurately modeled with regression equations, developed from the test data, and applied over the tested range of those variables, namely Mass of Fibrous Debris and Water Fiow Rate.

addi%n of stainless steel foil fragmems, which simulate Reflective Metallic l

l Insulation debris, increased the Head Loss across the Sure-Flow Strainer by about 20%, an increase ofless than 0.5 ft of water.

i

3 Summ:ry Repsrt en the Performance of Performance Centrccting, Inc.'s Sure-i Flow" Suctisn Strainzr with Veri:us Mixes cf Simul:ted pest-LOCA Debris, l

Rev.0 02/14/97 i

thick fibrous debris beds exhibited an effective fdtration efBeiency that approached e

j unity (i.e., acted almost as a perfect filter).

on this strainer prototype, the fibrous debris beds exhibited an apparent bed i

e j

compaction of approximately 24% (using the as-fabricated insulation density as a i

reference).

l the Sure-Flow Strainer, mounted in a horizontal position, did not cavitate, even when j

the tank was drained so that the strainer was about half exposed above the water level.

1 i

The particular strainer prototype was tested on a 24 inch NPS line and it had certain l

geometric features:

)

2 170 ft total surface area of perforated plate e

j 24 inch NPS attachment flange and Internal Core Tube e

e 40 inch outer diameter 48 inch active length and a 54 inch total length l

2 56 ft of circumscribed cylindrical surface area, including the ends thirteen disks with a width of 1.85 inches each j

e j

twelve gaps (between the disks)with a 2.00 inch width and n tota vol me of e

l about 10.3 ff holes in the Internal Core Tube that are smallest at the flange end a

.argest at e

i the opposite end; these are sized with a linear distribution, over the length of l

the Internal Core Tube, so as to provide equal Water Flow Rate from disk to disk and hence uniform water flow over the strainer's length.

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S mm ry Report en the Ptrfsrmance cf Perf:rmstee Centracting, hc.'s Sure-Fisw"Sucti:2 Strairr with Vari:us Mixes cf Simul:ted post-LOCA Debris, l

Rev. 0 02/14/97 -

While only one strainer prototype was tested at EPRI as part of the reported testing program, the results of the testing program can be used to verify a general predictive model that can then be used to predict the behavior for other sizes, with other Water Flow i

Rates and debris quantities. One such model, for predicting Head Loss across a fibrous and paniculate debris bed, has been~ developed by Science and Engineering Associates (SEA) for the United States Nuclear Regulatory Agency. It is based on the one-dimensional, flat plate filtration equations for flow resistance (i.e., for Head Loss) and is developed in Appendix B of NUREG/CR-6224 (Ref. 2). This PCI report suggests how l

l these equations can be modified to account to the three-dimensional shape of the Sure-l l

Flow Strainer which is cylindrical in outer shape and is made up of a number of stacked i

l disks. This can to be done to analytically to account for the gaps, between the disks, that j

fill with fibrous debris and thereby change the disks and gaps to a single, large cylinder l

which increases in diameter and length with increasing quantities of fibrous debris.

l Nevertheless, these equations, modified for three-dimensionality, are still based on the one-dimensional, flat plate filtration model that is the basis of those NUREG Head Loss equations.

L DESCRIPTION OF THE TESTED SURE-FLOW STRAINER PROTOTYPE The tested Sure-Flow Strainer prototype consists of a series of coaxial stacked disks

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that are equally spaced and mounted on an Internal Core Tube. Figure la is a photograph of the tested strainer prototype and Figure I b is a mechanical drawing. The l

Internal Core Tube is a pipe with holes in it. These holes are spaced so as to line up with the disks and the gaps (between the disks). They have a varying size: those holes closest i

to the flange end of the strainer are smallest and those at the far end of the strainer are i

largest, with those inbetween sized linearly so as to provide approximately equal water i

flow from disk to disk and from gap to gap. In addition, the Internal Core Tube is

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designed to keep all tubulent water flow (and thereby all high velocities) in the tube itself, away from the disks and the debris. PCI believes that this feature helps prevent compaction of the collected fibrous debris, thereby preventing an even greater increase in Head Loss.

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For structural reinforcement, each disk on the prototype has six (6) internal stiffener plates. These plates are radially oriented and are welded to both the core tube and the inside of the disks. The disks are all fabricated on their exterior from perforated metal i

plate. For this prototype, that material is 11 gauge steel with 1/8 inch diameter holes, spaced so as to give a 40% free area. Fabrication is such that each disk consists of two '

sheets of perforated plate welded to the Internal Core Tube and one strip of perforated j

l plate welded to the outside of the two sheets like the edge of a wheel, thereby creating a disk. Each disk is 1.85 inches wide and each gap is 2.00 inches wide. The outside shape L

of the strainer is that of a cylinder that is 48 inches long and 40 inches in diameter, all l

mounted around a 24 inch outer diameter Internal Core Tube with % inch thickness. The J

j 24 inch NPS flange is welded onto the end of the Internal Core Tube, six (6) inches from 4

l

Sumanry Riport en the Pzrfsrm:nce cf Pzrf rm nce Centr:cting,Inc.'s Sure-Fl:w* Suetio:s Strainr with Veri:us Mixes cf Simuisted post-LOCA Debris, Rev.0 02/14/97 l

1 the first disk. Therefore, the overall strainer length is 54 inches (i.e.,48 inches of active strainer plus 6 inches of attachment pipe). See Figure Ib.

1 Duke Engineering and Services, Inc. (DE&S) performed a structural evaluation of this strainer prototype and determined that its structural integrity was adequate for the Head j

Loss tests up to, but not above, about 19 feet of water. When that Head Loss limit was j

reached during a test, in some cases the water flow rate was reduced to keep the pressure l

differential across the strainer to less than or equal to that value and thereby allow us to collect data. It is noteworthy to point out that this pressure differential limit of 19 feet is actually approximately equal to the specified post-LOCA maximum hydrodynamic pressure for strainers at many BWR plants. PCIis currently supplying strainers to several l

BWR nuclear plants and, for structural robustness, these have been designed with greater

~ hickness steel for the Internal Core Tube, the addition oflongitudinal stiffeners for the t

Internal Core Tube, and the addition of more intemal disk stiffeners. These additional structural reinforcements will not interfere with either the internal water flow or with the external debris collection and that has been a very imponant design consideration is reinforcing the Sure-Flow Strainers for these nuclear plants.

It is important to point out that the tested prototype is a bolt-on, cantilever strainer, l

designed to be supponed by a BWR's attachment ECCS pipe in a radial orientation.

L Different plants may require other structural mechanisms, depending on the strainer size.

l For example, one nuclear utility has ordered two seventeen (17) foot long strainers, each l

containing three tee pipe connections. These long strainers are designed to be supported like a beam, at each end, by a pair of ring girders. The ECCS pipe connections will connect to the tees such that these pipe are oriented at 90 degrees with the strainer axis rather than in line with it. Nevertheless, the Internal Core Tube remains the basic

' structural " backbone" of this long strainer and each disk must be internally reinforced, just as it would be for a bolt-on, cantilever design strainer.

IL DESCRIPTION OF THE TEST FACILITY The tests at EPRI were all conducted by Continuum Dynamics, Inc. (CDI). The 1995 testing, sponsoredjointly by the BWROG and PCI, is summanzed in the BWROG's Utility Resolution Guidance, or URG (Ref.1). The CDI test report, Performance Contracting. Inc. ECCS Sure-Flow

• Strainer Data Report, Revision 0 (Ref. 3), gives the results of those tests sponsored by PCI and conducted in 1996. Chapter 2 provides a description of the test facility and the test procedures. The same facility was used and '

the same procedures were followed for both the 1995 and the 1996 performance tests at EPRI. There was no control over water temperature so that temperatu:re fluctuated and was therefore a little different on different days.

It is significant to point out that the test configuration and strainer mounting at EPRI j

included a 180 tee, a 90* long radius elbow, and several feet of straight pipe between the two pressure transducers used to measure Head Loss across the strainer. Therefore, 5

l

Summary Report es the Perf rmrnce cf Perfsrmenc2 Centracting,I c.'s Sure-Fl:w" Suetira Straizr r/ith Vari:us Mixes cf Simul:ted post-LOCA Debris, l,

02/14/97 Rev.0 the Head Loss measurements for the bare (i.e., with no debris) strainer, while relatively low, still included a pressure drop across these piping components. In this paper, a correction is made to determine the Corrected Head Loss across the bare strainer (i.e., the Corrected Head Loss is the pressure drop across the strainer only, without losses associated with these piping components).

IIL TEST RESULTS l

The 1995 test results are providad in the PCI report, The Development and Testing of Performance Contracting, Inc. 's Sure-Flow Stacked Disk Suction Strainerfor BWR ECCSLines, February 1,1996 (Ref. 4). Those 1995 test results are also contained in Appendix B of the BWR Owners' Group's Utility Resolution Guidance. Rev. 0 (Ref.1).

The 1996 tests results are provided both in the CD1 test report (Ref. 3) and in the PCI Memo for Record, QA Dedication ofStrainer Testing at EPRI, November 11,1996.

Note that,the water temperature for these 1995 tests was 58 to 60 F and that it was 69 to 70 F for the 1996 tests. Because water viscosity is dependent on water temperature, and since viscosity is about 20% lower for the higher water temperature, a correction will l

be made for those Head Loss values across debris beds.

I PCI performed a QA dedication of both series of tests and therefore documented the results separately from CDI. These results and those reported by CD1 were very close in value. For the purposes of this report, PCI has used their own readings rather than those reported by CDI. All were performed under a nuclear Quality Assurance Program.

l A. Bare Strainer Head Loss Table la: Experimental values of Water Flow Rates, Water Velocity, and Head Loss l

for the Bare Sure-Flow Strainer prototype tested at EPRI, October 28,1996 L

WATER -

INTERNAL WATER VELOCIW MEASURED FLOW RATE WATER VELOCIW SQUARED HEAD LOSS GPM FT/SEC FT'/SEC" FEET WATER l

0 0

0 0

1250 0.925 0.855 0.017 i

2500 1.849 3.42 0.083 3750 2.774 7.69 0.250 5000 3.699 13.7 0.500 6250 4.623 21.4 0.833 7500 5.548 30.8 1.250 8750 6.472 41.9 1.667 10000 7.397 54.7 2.000 Bare strainer Head Loss values, as measured in 1996, are given above as Table la.

These include the pressure drops across the bare strainer, the tee, the 90 long radius 6

Summary R: port on the Perf:rmInce cf Parfarm:nce Centrccting,Inc.'s Sure-Fl:w* Suc:isu Str iner with Varins Mixes cf Simul:ted post-LOCA D:bris, Rev. 0 02/14/97 elbow, and several feet of straight pipe. These measured values of Bare Strainer Head Loss, can be calculated as a function of Water Flow Rate in gallons per minute. This has been done in Figure 2 and clearly shows a relationship best described as a parabola, suggesting a flow rate, or water velocity, squared relationship. For further analysis, the Water Flow Rate was converted to Water Velocity, in feet per second, by dividing by the cross-sectional area of the inside of the 24 inch NPS, Schedule 30 pipe, an area of about 2

j 3.0 ft. These values are also shown in Table la.

i A regression analysis was then performed to determine a regression equation that best fits i

this test data. This was done as follows: Equation I was used in the regression analysis to determine the values ofA and B:

Eau. I HL (measured) = A + B'* V 2

where the value of coefficient A is very small since theoretically there is no head loss l

with no water velocity. Table Ib shows the results of the regression analysis of the Bare Strainer Head Loss data measured at EPRI on October 28,1996 (Ref. 3).

i i

Table 1b: Results of a regression analysis of Data in Table la of Measured Head Loss and Water Velocity for the Bare Strainer in the EPRI test configuration Regression Statistics Multiple R 0.997496 l

R Square. 0.994998 Adjusted R 0.994284 Square Standard 0.056796 Error Observation 9

ANOVA df SS MS F

Significance F Regression 1 4.491864 4.491864 1392.462 2.58E-09 l

Residual 7 0.022581 0.003226 Total 8 4.514444 Coeffbent Standerci tStat P-value Lower Upper Lower

. Upper 95.0%

s Error 95 %

95%

95.0%

7 intercept 0.01257 0.027532 -0.45651 0.661853 -0.07767 0.052533 -0.07767 0.052533 X Variable 0.03849 0.001031 37.31571 2.58E-09 0.036051 0.04093 0.036051 0.04093 i

l 7

Summ:ry R: port en the P rf:rm:nce cf P2rf:rmance Centracting,Inc.'s Sure-Fl:w* Suetim Strainer with Vari:ts Mixes cf Simul:ted post-LOCA Debris, c

Rev.0 02/14/97 The regression analysis determined the following values for the coefUcients: A=-

0.01257 and B = 0.03485 where V has units of ft/sec and HL has units of feet of water.

2 Since this relationship has correlation coefficient (R ) of 0.9950, this equation, of a squared dependence of Bare Strainer Head Loss on Water Velocity, appears to be a good fit. And, since Head Loss depends on Velocity squared, the flow is obviously turbulent over most of the velocities, therefore Head Loss is independent of water viscosity and hence independent of water temperature. (Note: this is not true of Head Loss across l

fibrous and particulate debris for large strainers; this flow through a debris bed is j

predominantly laminar and therefore linearly dependent on water viscosity).

A plot for calculated Head Loss values, referred to as Regression Head Loss and generated by using this regression equation fit of the test data, is given as the dashed (upper) curve in Figure 2.

These Regression Head Loss values included the Head Loss contributions of a 24" NPS, 90 elbow, a 24" NPS,180 tee connection, and several-(less than ten) LF of straight pipe.

See the BWROG's URG (Ref.1) for a description of the piping arrangement at EPRI and for the measurement locations. Therefore, a Corrected Head Loss, across only the bare strainer, by itself, without these piping components, should be calculated. The values of Corrected Head Loss should be less than the values of Regression Head Loss at corresponding values of Water Velocity (and Water Flow Rate) since Corrected Head Loss does not include the pressure losses associated with the piping components. This can be done by using the following general equation to calculate Head Loss across various piping components (see Ref. 2):

2 Eau.2 HL = K

• V / 2

• g where V = water velocity, ft/sec K = loss factor for the particular fitting 2

g = gravitational constant = 32.2 ft/sec HL = Head Loss, feet of water and Kw = = 0.6 for a 90 standard elbow (such as on the EPRI installation) and K,,.

- 0.5 for a straight,180 tee (this is estimated).

To calculate the Corrected Head Loss, the pressure drop contribution from the several LF of straight pipe can be ignored since it is such a short length. The Regression Head Loss values can then be corrected for Head Losses across the bare strainer alone, without the piping components, using Equation 3 below:

Eau.3 Corrected HL = Regression H.L - HLw a,

- HL.,.

l 8

3uuNEery Report cn the r#mma:ce cf Perf:rmrnce Contr:cting Inc.'s SAre- ~

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Fl:w" Suction Strainer with Vari us Mixes cf Simulated post-LOCA Debris, Rev.0 02/14/97 FIGURE 2 MEASURED, CALCULATED, AND CORRECTED VALUES OF HEAD LOSS ACROSS THE BARE STRAINER TESTED AT EPRI, OCTOBER 28,1996 1

I 2.00 e ACTUAL TEST DATA e' '

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0 1000 2000 30C0 4000 f400 6000 7000 8000 9000 10000 WATER FLOW RATE, GPM Figure 2 above can be used to select values for both Regression Head Loss (the heavy dashed line) and Corrected Head Loss (the solid dark line) for a desired water flow rate.

For example, at 10,000 gpm (V = 7.43 ft/sec), the Corrected Head Loss = 1.16 feet of water, about 45% less than the measured value of 2.08 feet of water.

4 l

It is interesting to compare the Corrected Head Loss to the estimated pressure drop or head loss were no strainer attached to the end of a 24 inch NPS pipe. Equations in Ref. 6 -

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can be used to calculate a coefficient for a sudden contraction of water, from a pool into a pipe. Using Ref. 6, PCI determined that this Coefficient of Contraction, C, is equal to about 0.62. This value can then be input into Equation 4 below to calculate what we will refer to as the No Strainer Head Loss:

4 Equ. 4 HL = ( 1/Cc - 1)2 V /2g = 0.37 V /2g 2

2 The light dashed curve on Figure 2 above shows the prediction for the No Strainer Head Loss, or that resulting only from entrance losses of flow being drawn into a 24 inch NPS pipe. It can be seen that these entrance losses are responsible for about 27 % of the head loss across the bare strainer by itself, namely the Corrected Head Loss. That suggests that the remainder, representing 73% of the Corrected Head Loss, results from the strainer itself.

9

l 1 Summ:ry Report en the Perf:rmarce cf Perfsrmance Ccatracting, Inc.'s Sure-l.

Fl:w" Sueti:n Strai2cr with Vcri:us Mixes cf Simul 2ted post-LOCA Debris, 02/14/97 Rev. 0 B. Strainer Head Loss with Simulated Debris Table 2 below summarizes all the results for the testing conducted at EPRI on this Sure-Flow Strainer prototype. For the purposes of distinguishing between the 1995 and the 1996 tests, PCI has used the prefix of"95 " or "96 " to designate the corresponding data.

In both cases, the Clean Strainer Measured Head Losses, referred to in Section A above, were first subtracted so that the values reported on Table 2 are for Head Loss across the debris bed only.

TABLE 2 l

Summary of Actual Head Loss Test Data from EPRI j

1995 and 1996 Measured Data-l All Head Loss Values in Feet of Water l

TEST NO.: 95-2 95-3 95-4 95-5 96-2 96-3A 96-3B 96-3C 96-3D 96-3E 96 4 96-5 MASS 17 25 3

50 25 100 150 200 250 300 100 200 FIBERS l

(LSS-)

Mass cP 85 100 100 100 100 0

0 0

0 0

100 100 (Las.)

l AREA oF 0

0 0

0 800 0

0 0

0 0

0 0

FotL (FT'l WATER 57 58 59 58 69 69 70 71 72 73 69 70 TEMP,*F 2500 gpm 0.58 0.83 0.00 2.29 0.96 4.65 6:15 8.32 9.65 5.40 10.73 3000 gpm 13.00 3500 gpm 13.67 3750 gpm 1.01 1.46 0.01 3.81 1.60 7.58 10.58 13.66 16.16 8.66 4000 gpm 16.58 19.17 5000 gpm 1.53-2.13 0.16 5.42 2.33 6.08 10.00 13.83 17.75 12.25 6250 gpm 14.75 7500 gpm 1.67 2.42 0.27 8.08 2.95 10000 gpm 1.67 2.58 0.00 '10.17 4.34 In most of the tests, the debris was collected on the strainer using a constant 5000 gpm Water Flow Rate, then after its collection, the Water Flow Rate was varied to allow the generation of Head Loss data for other values. However, for Test No. 96-3E (300 lbs. of Fibrous Debris and no CP Particulate) and for Test No. %-5 (200 lbs. of Fibrous Debris and 100 lbs. of CP Particulate), the Water Flow Rate was reduced to 4000 gpm to keep the total Head Loss below about 19 feet of water, judged by PCI's structural consultants.

(i.e., Duke Engineering & Services, Inc.) to be the maximum allowable pressure differential across this strainer prototype. In fact, for all of the 19% tests, this upper limit of 19 feet of water was observed by PCI as the maximum allowable Head Loss, thereby preventing the collection of Head Loss data at higher than 5000 gpm Water Flow Rates for all but Test No. 96-2.

l 10

Summary RIport c2 the Perhrmzce cf Parf:rmance Centrccting, Incb Sur Fisw" Sucti:n Straintr with Veri us Mixes cf Simul:ted post-LOCA Debris, Rev.0 02/14/97 Figure 3 below shows the results of the debris collection, as Head Loss vs. Time, for Tests Nos. 95-3 and 96-2. For the first of these two tests,25 lbs. of Fibrous Debris and 100 lbs. of CP Particulate were added; in the second, those same quantities of Fibrous Debris and CP Particulate were added but elso 800 square feet of stainless steel foil, simulating debris from Reflective Metallic Insulation, was added. As can be seen, both sets of data followed the same time constant and the Head Loss results, at particular times, are close in value, with the addition of the RMI foil increasing Head loss by about

% feet of water, representing about 20% after correction for water temperature. It can also be seen that for this test configuration, using 5000 gpm and a 50,000 gallon tank, that it took approximately 50 minutes to reach an equilibrium Head Loss. This pattem j

was found for all the debris collection tests, for which debris collection was performed at 4000 or 5000 gpm, as is clearly shown in the transient plots included in Reference 4..The 1996 test data, collected using about 70 F water, was correc:ed for 60 F water temperature in order to compare it to the 1995 test data which was collected with about 60 F water. This same correction, to 60 F, will also be made for other Head Loss data presented in this paper unless noted otherwise.

FIGURE 3:

EPRI TESTS NTH AND WITHOUT SS FOIL:

4 HEAD LOSS VS. TIME WITH 5000 GPM OF ROOM WITH 25 LBS. SHREDDED NUKON & 100 LBS. CP PARTICULATE CORRECTED FOR 60 DEGREES F WATER 3

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- 40 45 50 TIME FROM START OF TEST (MINUTES) i 4

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d Summary Report c2 the Pzrf rmance cf Pcrf:rmrnce Centracting, Inc.'s Sure-

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Fisw" Suctics Strainr with Vari:us Mixes cf Simul:ted post-LOCA D:bris, Rev.0 02/14/97 e

Figures 4 and 5 (following) show the results taken from the series of Tests 96-3A r[

through -3E. In these tests, no CP Particulate was added to the tank. Instead, fibrous debris was added to the test tank in increasing quantities, starting out with 100 lbs., then increased in 50 lbs. increments till 300 lbs. was added in total. ' Figure A-3 from the CD1

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report (Ref. 3) shows the sequencing clearly in the transient Head Loss graph.- Figure 4 below shows that Head Loss is roughly linearly dependent on Water Flow Rate, for a 1

2 given quantity of Fibrous Debris. Figure 5 below shows clearly that Head Loss is

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approximately linearly dependent on Mass of Fibrous Debris for a given Water Flow Rate i

through the strainer.

In both cases, there was no CP particulate and the linear behavior can only be considered for the range of the tested variables. However, the essentially linear dependence of Head i

Loss on Water Flow Rate is expected, per the USNRC NUREG/CR-6224 Equations, for j

predominantly laminar flow through a fibrous bed collected on the strainer. For Head j

Loss dependence on Mass ofFibrous Debris, the dependence can be expected to be es_sentially logarithmic with very large quantities of Fibrous Debris. This logarithmic behavior will be explained later in this report. For the range over which these tests were conducted (i.e., up to 300 lbs. of Fibrous Debris on this particular strainer prototype), the dependence of Head Loss on Mass of Fibrous Debris is, as expected from the Head Loss

[

equations in Reference 2, also essentially linear.

For those tests with 100 lbs. of CP Particulate, graphs similar to Figures 4 and 5 can be plotted. The four Tests 95-3,95-5,96-4, and 96-5 all used the same quantity of CP particulate, namely 100 lbs., and 25,50,100, and 200 lbs. of Fibrous Debris,

[

respectively. The Head Loss dependence on Water Flow Rate, for the four different j

quantities of Fibrous Debris, is shown graphically in Figure 6. Again, the dependence on Water Flow Rate is essentially linear. The Head Loss dependence on Mass of Fibrous Debris, for several different Water Flow Rates, is shown in Figure 7. Again in this case, y

the dependence is essentially linear, as was the case without any CP Particulate.

1 Other than Tat No. 95-2, only two different quantities of CP Particulate were used for all of these tests: either 0 lbs. or 100 lbs.

I 1

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FIGURE 4:

l HEAD LOSS VS. FLOW RATE FOR THE SURE-FLOW STRAINER WITH l

FIBROUS DEBRIS AND NO CP PARTICULATE l

HEAD LOSS VALUES CORRECTED FOR 60 DEGREES WATER

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100 LBS. FlBROUS DEBRIS y'

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150 LBS. FIBROUS DEBRIS s -

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j i - 250 LBS. FIBROUS DEBRIS l, " '

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1000 2000 3000 4000 5000 WATER FLOW RATE, GPM

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FIGURE 5:

HEAD LOSS VS. MASS FIBROUS DEBRIS FOR THE SURE FLOW

' STRAINER WITH FlBROUS DEBRIS AND NO CP PARTICULATE l

HEAD LOSS VALUES CORRECTED FOR 60 DEGREES WATER 20 --

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Rev. 0 02/14/97 FIGURE 6:

i TEST DATA ON PCTS SURE. FLOW STRAINER AT EPRl:

l HEAD LOSS VS. FLOW RATE FOR SEVERAL QUANTITIES OF FIBROUS i

DEBRIS, WITH 100 LBS. OF CP AND 60 F WATER I

l s

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25 LBS. FIBROUS DEBRIS g

I - 50 LBS. FIBROUS DEBRIS

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FIGURE 7:

TEST DATA ON PCPS SURE-FLOW STRAINER TESTED AT EPRI:

HEAD LOSS VS. MASS OF FIBROUS DEBRIS,100 LBS. OF C.P., AND 60 F WATER l

20 -

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Fl:w" Suction Straiter with Vcrins Mixes cf Simulated post-LOCA Debris, Rev.0 02/14/97 l

C. Apparent Filtration Efficiency After the completion of all the tests, PCI took water samples to be analyzed for per cent solids. A comparison of these were used to calculate the Apparent Filtration Efficiency l

of the fiber bed on the strainer. The per cent solid at the beginning of each test can be determined by taking the total quantity of CP particulate and assume it is uniformly distributed throughout the approximately 50,000 gallons of water in the EPRI tank and j

piping system. Table 5 gives the results of tests for Apparent Filtration Efficiency. It is l

worth noting that these values ranged from a low of 41%, for a very thin layer test, Test l

No. 95-4, up to almost unity for the thickest layers in Tests No. 96 4 And 96-5.

Table 5: Estimated Values of Apparent Filtration Efficiency for Tests with Combined NUKON Fibrous Debris and CP Particulate Test No.

95-2 95-3 95-4 95-5 96-2 96-4 96-5 l

Mass CP 180*

180*

180*

180*

170 160 180 at t=0 mg/l mg/l mg/l mg/l mg/l mg/l mg/l j

Mass CP J

at test end 51 mg/l 4 1 m g/l 107 mg/l 35 mg/l 30 mg/l 5 mg/l 12 mg/l i

Mass CP j

removed 129 mg/l 139 mg/l 73 mg/l 145 mg/l 140 mg/l 155 mg/l 168 mg/l Apparent l

Filtration 72 %

77 %

41 %

81 %

82 %

97 %

98 %

I Efficiency l

• Indicates a value calculated by using measured weight of CP and estimated volume of I

water in the tank and piping system.

D. Fibrous Bed Compaction l

A factor which affects head loss across a fibrous bed is the effective bed compaction.

This compaction probably results from the viscous effects of water flowing past the fibers collected on the surface of the strainer. For the purposes of most of the calculations, we use the "as fabricated" insulation density which is 2.4 lbs./ft' for NUKON Base Wool, the insulant used in the fabrication of NUKON Insulation blankets.

l To determine the effective bed compaction, PCI measured the bed thickness following Test No. 96-05. This was done using a long pole and inserting it into the wet bed, l

following the draining of the tank. Figure 10 is a photograph of this being done. This measurement technique gave an approximate thickness, from the outer edge of a disk to.

the outer edge of the bed, of 8 % inches.' A hand calculation can show that the bed volume was approximately 56 ft' whereas it would have been approximately 73 ft' were there no compaction. This allows for 10.3 ft' of fibers to collect first in the gaps between the disks. Taking the quotient of the actual and the theoretical gives a ratio of 0.76, or a compaction of(1 - 0.76 ) = 24%.

15

l Summ:ry Reporien thsPirf5rmince~cf Peiform:ncedentiaciins iniSSurI

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Fl:w" Sucti:n Strzin:r with Vari:us Mixes cf Simulited post-LOCA Debris, R v. 0 02n4/97 IV. REGRESSION ANALYSIS OF TEST DATA Head Loss across the debris bed: Calculations for Head Loss across the debris (i.e.,

combination of NUKON fibers and corrosion product particulate) on the strainers are performed by first developing a regression equation for some of the data given in Table

1. For the purposes of predicting behavior of this strainer for different water flow rates, different diameters and lengths and hence different surface areas, PCI developed a couple of MS Excel spreadsheet programs. To do this, several assumptions were made:

1. Results from Tests Numbers 95-3,95-5,96-4, and 96-5 can be analyzed by reggession to determine the Head Loss dependence on Water Flow Rate and Strainer Surface Area. The prototype strainer's tested behavior can then be accurately scaled by l

dividing its water flow rate and its mass of fibrous (NUKON) debris by its 2

circumscribed surface area, namely 56 ft where this strainer had a 40" diameter, a l'

48" active length, and a 24" Internal Core Tube (Note: for Test No. 96-5, a circular disk was bolted onto the test strainer's end disk, reducing the circumsciibed surface area toS3 ft'). This assumption is conservativesince as more debris buildup occurs, 2

the strainer's surface area actually grows, thereby not remaining at 56 ft,

2. A given strainer's behavior can be accurately predicted by treating the strainer as a large cylinder that has similar behavior, based on its cylindrical surface area, as the tested prototype. As shown in the EPRI tests, the NUKON fibrous debris will collect all over the strainer and fill all the voids, gaps, etc. This should be valid when the strainer has disks that are 1.85" wide and are separated by 2.00" wide gaps, the same as the tested strainer prototype.

3. The tested corrosion product particulate used in the EPRI Head Loss tests accurately simulates all the specified particulate in a particular plant's specification.

4. Calculated Head Losses at 70*F can be recalculated for other, higher temperatures by simply multiplying by the ratio of the kinematic viscosities at each of the two temperatures. This is based on the derivation of Equ. B-32a in NUREG/CR-6224 (Ref.1). This also assumes that the Head Loss across a fibrous debris bed is dominated by the laminar, viscosity dependent portion of that equation; this assumption can be validated by calculations which show that the turbulent, non-viscosity portion of the equation contributes little to the calculated Head Loss at some other water flow rate and some other quantity of fibrous debris.

5. The debris build-up on the new strainers is uniform over its length and the Head Loss is uniform across any part of the strainer.

6. To calculate Head Losses at other values of mass ratio values than those encompassed by the tests, namely 4:1 to 1:2, one can use the portion of Equ. B-32a (Ref.1) that includes the mass ratio:

Mass Ratio Correction Factor = ((1 + 0.54 (new ratio))/(1 + 0.54 (ref. ratio)))'5 16

,a 2

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Summary R: port en the Perf rmmce cf P rfsrmance Centrccting,Inc.'s Sure-Finw" Sueti:n Str;irer with Veri:us Mixes of Simulated post-LOCA Debris, Rev.0 02/14/97 l

Table 2 gives the results of setting up a regression analysis for Head Loss as a function of j

Flow E ae and Mass of NUKON Fibrous Debris. As explained in the Assumption 1 l

above, each of these two independent variables is first divided by the test strainer's l

surface area, then a new independent variable that is the product of those first two, and l

then use the Excel regression program to generate coefficients for the following equation:

l Equ. 5 HL

= A + B * (Q/A, ) + C * (M/A, ) + D * (Q/A!) (M/A, )

where Q

= strainer flow rate, gpm A,

= strainer's cylindrical surface area, sq. ft.

Mr

= mass of NUKON fibers, Ibs.

HL

= strainer head loss, feet of water Table 2 shows the results of the regression analysis using the test data:

A = 0.7696 B =-0.02292 C = -0.5406 D = 0.08916 l

2 where value of R = 0.9828 for this analysis, indicating an excellent correlation fit over the range of these tests.

l l

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17 l

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l Summrry Report en the Perf:rmaca of Perf:rmance Centracting. Inc.'s Sure-Fl:w Sueti:n Strainer with Varins Mixes cf Simutzted post-LOCA Debris,

- Rev.0 02/14/97 Table 3: EPRI Head Loss Test Data Used for a Regression Analysis EPRI HEAD LOSS DATAWITH 100 LBS. CP AND 25,50,100, AND 200 LBS. NUKON, WATER FLOW RATES 0 TO 10,000 GPM HEAD LOSS VALUES CORRECTED FOR 60 DEGREES F WATER

}

FLOW MASS MASS MASS HEAD FLOW MASS CP NUKON CP/

MASS X LOSS RATE NUKON MASS / AREA X RATE MASS FLOW PER PER FLOW NUK RATE AREA AREA,-

RATE / AREA GPM LBS LBS LBS/LBS GPM-LBS FEET GPM/SQ LBS/SQ GPM-LBS/FT(4)

WATER FT FT

(

TEST NO.

95-3 0

100 25 4

0 0.00 0

0.446 0-l 2500 100 25 4

62500 0.83 44.6 0.446 19.93

.3750 100 25 4

93750 1.48 67.0 0.446 29.89 l-5000 100 25 4

125000 2.13 89.3 0.446 39.86 7500 100 25 4

187500 2.42 133.9 0.446 -

59.79 10000 100 25 4

250000 2.58 178.6 0.446 79.72 95-5 0

100 50 2

-0 0.00 0.0 0.893 0.00 2500 100 50 2

125000 2.29 44.6 0.893 39.86 3750 100 50 2

187500 3.81 67.0 0.893 59.79 5000 100 50 2

250000 5.42 89.3 0.893 79.72 7500 100 50 2

375000 8.08 -

133.9 0.893 119.58 j

10000 100 50 2

500000 10.17 178.6 0.893 159.44 96 4 0

100 100 1

0 0.00 0.0 1.786 0.00 2500 100 100 1

250000 8.20 44.6 1.786 79.72

)

3750 100 100 1

375000 9.95 67.0 1.786 119.58 5000 100 100 1

500000 14.08 89.3 1.786 159.44 6250 100 100 1

625000 16.97 111.6 1.786 199.30 96-5 0

100 200 0.5 0

0.00 0.0 3.774 0.00 2500

.100 200 0.5 500000 12.33 47.2 3.774 178.00 i

3000 100 200 0.5 600000 14.94 56.6 3 774 213.60 i

3500 100-200 0.5 700000 19.15 66.0 3.774 249.20 l

4000 100 200 0.5 800000 22.03 75.5 3.774 284.80 i

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Fisw" Sueti:s Strair:r with Vari:us Mixes of Simul ted post-LOCA Debris, l

Rev.0 02n4/97 l

i Table 4: Results of Regression Analysis of Data in Table 3 l

and Using Equation 5 for a Regression Fit

SUMMARY

OUTPUT Regressen Statistics Multiple R 0.991381 R Square 0.982837 Adjusted 0.979976 R Square -

Standard 0.975788 Error

- Observati 22 l

ons l

ANOVA di SS MS F

Signi6cance F Regressio 3 981.4552 327.1517 343.5886 4.5185E-16 n

Residual 18 17.1389 0.952161 Total 21 998.5941 l

CoefMcient Standard tStat P-value Lower 95%

Upper Lower Upper i

s

- Error 95%

95.0%

95.0%

intercept 0.769632 0.605264 1.271563 0.219713 -0.5019821 2.041246 -0.50198 2.041246 l

X

' 0.05292 0.006621 -3.46179 0.002783 -0.0368284 -0.00901 -0.03683 -0.00901 l

Variable 1 X

-0.5406i 0.317771 -1.70126 0.106104 -1.208226 0.127001 -1.20823 0.127001 Variable 2 X

0.089155 0.004913 18.14504 5.13E-13 0.07883243 0.099478 0.078832 0.099478 Variable 3 l

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SammIry Rrport en tha Psrfsrm:nce cf Parfcrmnace Cc:trccti:g,Inc.'s Sure-Fl:w" Sueti:2 Str:irr with Veri:us Mixes of Simul ted post-LOCA Debrisi i

Rev.0 02/14/97 l

Using this Equation 5, Head Loss values, for a particular plant's strainers, can be generated for a case where the suppression pool has water temperature T, the strainers a constant Water Flow Rate Q, a total of Mr Pounds of shredded NUKON Fibers and Mcp pounds of CP Particulate reach the strainers, the strainers have diameters D and lengths 1

L, and an infinite period of ECCS pump operation. The following example problem shows how this can be accomplished:

~

Example Head Loss Problem Using the Regression Equatien 5:

Suppose a plant has four equal sized strainers on a common ring header which draws a total of 20,000 gpm. Each strainer is a Sure-Flow stacked disk strainer, with all disks of L

the same size, each strainer is 4 feet long and 45 inches in diameter, and each is mounted on a 20 inch NPS pipe. Assume, for the purposes of design conditions, that the water temperature is 180 F, that 800 lbs. of CP particulate and other particulate are in the suppression pool, and that 333 cubic feet of shredded NUKON insulation are transported to the pool. Ignore any particulate or fiber sedimentation and assume 100% filtration efficiency of the particulate by the fibers on the strainers. Also, assume that NUKON insulant has an as-fabricated density of 2.4 lbs/ cubic foot.

Solution:

First, calculate the cylindrical surface area of each strainer. Including the end disks, this works out to be about 70 fiz. Therefore, 2

2 Q/A = (20,000 gpm total / 4 strainers) / 70 ft cyl. Area = 71.4 gpm/ft and M/A = ((333 ft' fibers / 4 strainers ) * (2.4 lbsift') / 70 ft2 = 2.85 lbs1 ft' Putting these into Equation 5, the Head Loss can be calculated for ambient water:

HL60 = 15.7 feet of water at 60 F water, which has a kinematic viscosity of 1.217 x 10 5 ft j3,c, 2

This Head Loss can now be corrected for 180 F water, which has a kinematic viscosity 2

of 3.85 x 10" ft /sec:

4 HL so - 15.7

• 3.85 x 10 /1.217 x 10 5 = 5.0 feet of water.

i This can now be corrected for the Mass Ratio of CP to fibers:

Mass Ratio CP : Fibers = 800 lbs. / (333 ft'

• 2.4 lbs/ft') = 1.00 4

This compares to the range of the tested values. For EPRI Test No. 96-4, the Mass Ratio l

was also 1.00. Therefore, no correction will be made for mass ratio. Hence, the 20 e

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Szem:ry Report es th2 Perf:rmace cf Perf:rm:nce Centracting, Iac.'s Sure-. _ _ _. _. __

Fl:w" S ctio:s Straiser with Verious Mixes cf Simulated post-LOCA Debris, Rev.0 02/14/97

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l predicted Head Loss across each strainer, which is 45 inches in diameter and 4 feet long, is 5.0 feet of water at 180 F. This problem is solved.

l V. THEORETICAL ANALYSIS OF STRAINER BEHAVIOR l

Figures 8,9, and 10 are photographs taken of the strainer following Tests Nos. 95-3,95-5, and 96-5, respectively (and following the draining of the tank). These were tests conducted with 100 lbs. of CP Particulate and 25,50, and 200 lbs. of Fibrous Debris t

respectively. Figure 8 shows that the gaps, between the disks, have become partially filled with fibrous debris and the disks themselves have also become more or less -

covered with debris when 25 lbs. were added in Test 95-3. Note that 25 lbs. of fibrous debris corresponds to about 1,0.3 ft' of debris volume (based on the as-fabricated insulation density of 2.4 lbs./ft'), which approximately equals the volume of the twelve gaps between the thirteen disks. Figure 9 shows that the twelve gaps have become 4

completely filled with fibrous debris when 50 lbs. of fibrous debris (corresponding to a volume of about 20.7 ft' using the as-fabricated insulation density of 2.4 lbs./ft') was added in Test 95-5. Figure 10 looks similar to Figure 9 except that the thickness of the i

debris bed is even thicker, which it should since 200 lbs of fibrous debris was added for this Test 96-5.

The debris collection behavior is evident: for the firn 25 lbs. (10.3 ft') of fibrous debris, 2

and possibly a little more, the strainer behaves as cae that has the 170 ft of flat plate surface area, the actual surface area of perforated metal plate on the strainer prototype.

1

- For fibrous debris quantities greater than that, the strainer starts to behave like a simple cylindrical shaped strainer after the gaps are filled. The surface area of the 2

circumscribing cylinder, including the ends of the disks, is about 56 ft, significantly less than the 170 ft of perforated plate. With the addition of greater quantities of fibrous debris (i.e., greater than a volume of at least 10.3 ft' which is what fills the gaps), the l

~

effective surface area will increase due to the increasing effective outer strainer diameter i -

resulting from the increasing Fibrous Debris thickness. This was noted following Test 96-5 when a measurement of the debris bed showed that it had a thickness between 8 and 9 inches. Assuming an 8 % inch thick debris bed over the entire strainer, its outer surface 2

area was then about 91 ft,

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shredded fibrous debris and 100 lbs. of CP particulate) l l

1 22 4

Summary Report on the Performance of Performance Contracting, Inc.'s Sure-l Flow" Suction Strainer with Various Mixes of Simulated post-LOCA Debris, Rev.0 02/14/97 7

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Figure 10 - Photograph of the tested strainer following Test No. 96-5 (with 83.3 ft' of l

shredded fibrous debris and 100 lbs. of CP particulate)

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l When behaving like a strainer with 170 fl of surface area, this prototype follows the one-l dimensional, flat plate NUREG equations for Head Loss. This can be seen from Table 2, for Test No. 95-3 (i.e.,25 lbs. of Fibrous Debris), which gives a good comparison l

between predicted and experimental results following the NUREG filtration equations.

However, for Test No. 95-5 (i.e.,50 lbs. instead of 25 lbs.), the actual measured Head 2

Loss was about twice that predicted assuming flitt plate behavior with the full 170 ft of perforated metal plate. Also, of course, for Tests Nos. 96-4 and 96-5, which used 100 lbs.

2 j'

and 200 lbs., of fibrous debris respectively, the use of 170 ft of surface area and the one-dimensional NUREG filtration equations underpredicts Head Loss. With this behavior, it l

was realized that some modification to the NUREG filtration equations would be necessary. To account for the cylindrical shape of the strainer, one-dimensional, flat plate equations for a cylindrical strainer were developed staning with the NUREG equations.

Further modification, accounting specifically for the filling of the gaps with fibrous debris, can be performed to account for the more complex three-dimensional behavior of the strainer and its impact of debris collection patterns.

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Fl:w" Suctin Str;inr with Veritus Mixes cf Simulated post-LOCA Debris, i

Rev. 0 02/14/97 For comparison, Figure 11 shows a lower, straight curve for the predicted Head Loss of a

)

2 one-dimensional, flat plate,170 ft 0f surface area and also an upper curve for a simple cylindrically shaped strainer that has no disks or gaps. The cylindrical strainer is assumed to have the same length and diameter as the tested prototype strainer. Figure 11 also shows a third curve for the three-dimensional strainer which first acts like a 170 ft2

)

strainer, then, after the gaps are filled with Fibrous Debris, behaves like a cylindrically shaped strainer. It should be noted that the simple cylindrical prediction is overly conservative for the tested prototype. This is because it does not account for the firs 25 l

lbs. of the debris becoming trapped by the gaps between the disks and then becoming, essentially, a cylindrical strainer.

2 A comparison of the equations used in Figure 11 for'the 170 ft surface show how the Head Loss values.were generated for one-dimensional debris collection on a flat plate i

strainer. Letting:

Mep/Mr = CP Particulate: Fibrous Debris Mass Ratio collected on the strainer th

= thickness of the Fibrous Debris bed, inches (this accounts for bed compaction described in Section III.D above)

A,

= strainer surface area, ft' Q

= Water Flow Rate, ft' / sec i

HL

= Head Loss across the strainer, feet of water we can write Equation B-32a from NUREG/CR-6224 for 60" F water and modify it for 70 F water by multiplying the coefficient 10 by the ratio of kinematic viscosities at 70 and 60" F:

Equ.6 HL = 8.7 * (1 + 0.54

• M p/Mr) 35

• th

• Q/A, C

j

+ 4 * (1 + 0.54

• Mcp/Mr)

• th * (Q/A.) 2 i

This one-dimensional flat plate equation (written in Cartesian coordinates) can then be 1

modified for one-dimensional cylindrical surfaces (using cylindrical coordinates) by means ofintegrating Head Loss as a function of strainer diameter. Because the surface area, A, = pi

• D,

• L, we can derive the modified equation for ey!inders:

D, = actual diameter of the strainer, inches Dr = total diameter of the strainer plus the Fibrous Debris bed, inches (accounting for bed compaction described in Section IV.D above)

Lr = effective strainer length, including the debris bed, ft.

I-Equ.7 HL = 8.7 * (1 + 0.54

• Mcp/Mr) '5

• Q

• In (Dr/D, ) /(2

• pi

• Lr)

(

+ 4 * (1 + 0.54

• Mcp/Mr) * (Q / (2

• pi

• L)2 ) * (2/D,- 2/Dr) e 24 l

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EummaryIXVdNGIo Perfsrm :ce culr5Fnferm:tce Ccctrzcti:g,Unc.'s Sure-

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Fisw" Sueti:s Strairtr with Vari:us Mixes cfSimulated post-LOCA Debris, i '

l Rev.0 02/14/97 f'

l There are some details required to calculate the values of Drand L, based on some of the l

collected fibrous debris becoming trapped in the gaps and the rest collecting on a simple l

cylindrical surface. In essence, however, the calculated Head Loss will follow the i

unmodified NUREG Equation, given as Equation 6 above, till the volume of fibers approximately equals the volume of the gaps between the disks, call this volume Vro,

l after which the remaining added fibers will build up on the strainer surface as ifit were a l

simple cylinder. At that point, the Head Loss will be given by the logarithmic Equation 7 plus a correction added to this Equation 7 Head Loss, namely that of the Head Loss with only Vro ft' of fibers, as given by Equation 6.

Figure 11 below shows a prediction for this logarithmic behavior with a strainer of the same outer dimensions (i.e., length and diameter) as the tested prototype with 4000 gpm of 70 F water flow. There are three curves: 1) one for the simple flat plate, as given by Equa6 ion 6 above, b) a second for a simple cylinder, as given by Equation 7 above, and c) a third which describes the stacked disk behavior, where a volume of fibers = Vro first fills the gaps between the disks and afterwards the strainer behaves like a simple l

cylinder. This last curve, for the stacked disk, is conservative when compared to the test data and obviously would not have the strong discontinuity resulting from the simple l

model described above. More work is needed to make it less conservative and hence l

more accurate in describing the behavior of the Sure-Flow Strainer tested. This work is i

l' being performed by Innovative Technologies, Inc. and will not be described here.

FIGURE 11 HEAD LOSS VS. VOLUME OF FIBERS USING 70 F WATER AND THREE DIFFERENT MODELS FOR HEAD LOSS ON THE TESTED SURE-FLOW STRAINER WITH 4000 GPM & 100 LBS. CP, 25.0

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- ------ -Summ ry Report en the PeWrmaice oWoW6DGDEiB Flow" Sueti:n Strainer with Vari;us Mixes cf Simulated post-LOCA Debris, 02/14/97 Rev.0 VL CONCLUSIONS A stacked disk strainer prototype was tested to determine its Head Loss performance over a wide range of Water Flow Rates and Mass of F'brous Debris and for one quantity of Corrosion Product particulate. Mass of Fibrous Debris was varied from zero to 300 lbs.,

Mass of Carrosion Product Particulate was varied between 0 and 100 lbs., and Water Flow Rate was varied between zero and 10,000 gpm for this single strainer prototype.

From these tests, the following conclusions could be reached about the behavior of the Sure-Flow Strainer prototype tested:

the bare strainer (i.e., with no debris) showed a very low Head Loss behavior and that I

Head Loss is linearly dependent on the square of the entrance (i.e., at the strainer's nozzle) water velocity.

its Head Loss behavior is essentially linearly dependent on both Mass of Fibrous Debris and Water Flow Rate, the addition of 100 lbs. of CP paniculate increases Head Loss across the strainer by e

about 60%,

the Head Loss behavior can be accurately modeled with regression equations, e

developed from the test data, and applied over the tested range of those variables, namely Mass of Fibrous Debris and Water Flow Rate.

addition of stainless steel foil fragments, which simulate Reflective Metallic Insulation debris, increases the Head Loss across the Sure-Flow Strainer by about 20%.

thick fibrous debris beds exhibited an effective filtration efficiency that approached unity (i.e., acted almost as a perfect filter).

on this strainer prototype, the fibrous debris beds exhibited an apparent bed compaction of approximately 24% (using the as-fbricated insulation density as a reference).

the Sure-Flow Strainer, mounted in a horizontal position, did not cavitate, even when the tank was drained so that the strainer was about half exposed above the water !evel.

26

Sqmm ry Report ca the Pe form nce ef Perf rmzc2 Ccntracting,Inc."s Sure-r a

FI;w" Srctica Strainr with Vcrious Mixes cf Simulated post-LOCA Debris,

~

Rev,0 02/13/97

References:

1. Utility Resolution Guidance for ECCS Suction Strainer Blockace. General Electric Nuclear Energy Co., Report No. NEDO-32686, Rev. O, Class 1, November,1996.

2. Parametric Study of the Potential for BWR ECCS Strainer Blockace Due to LOCA Generated Debris, prepared by G. Zigler, J. Brideau, D.V. Rao, C. Shaffer, F. Souto, W. Thomas of Science and Engineering Associates, Inc., prepared for U.S. Nuclear Regulatory Commission, Repon Number NUREG/CR-6224, September,1995.

3. Performance Contractine. Inc. ECCS Sure-Flow

• Strainer Date Renon. Revision 0, prepared by Continuum Dynamics, Inc., Repon Number WO4536-01, written by Kaufman, Andrew E., Dient, Robert W., and Louderback, Richard G., prepared for Electric Power Research 1nstitute, December,1996.

4. The Development and Testina of Performance Contractina. Inc 's Sure-Flow

• Stacked Disk Suction Strainer for BWR ECCS Lines. by Gordon H. Han, February 1, 1996.

5. Performance Contracting, Inc. Memofor Record, "QA Dedication of Strainer testing at EPRI", by Gordon H. Han, November i 1,1996.

6. Merritt, Frederick F., Editor, Standard Handbook for Civil Eneineers, Third Edition, McGraw Hill Book Company,1983, p. 21-27.

Written by:

e 6 /.L4Si Gordon H. Hart, P.E.

Date:

kb l4,/W7

/

Reviewed and Approved by:

/

6 /W9W C'arl s. Nuzmand.W Hydraulic ConsultanV Date: /

28