ML20094D172
| ML20094D172 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/06/1991 |
| From: | Glissmeyer J Battelle Memorial Institute, PACIFIC NORTHWEST NATION |
| To: | Khadijah West Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18036A687 | List: |
| References | |
| CON-FIN-L-1866 TAC-M80018, NUDOCS 9111140109 | |
| Download: ML20094D172 (15) | |
Text
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hTriClMDVD 3 0Battelle Pacihc Northwest laboratones Banehe Bowiriard P O Bon 999 Richland. W athinpon 99M2 mephone #5w376 8552 Septembar 6, 1991 Mr. K. Steven West NRR/PMSB Hailstop 12 H26 U.S. Nuclear Regulatory Commission Washington, DC 20555 Sub.iect:
L-1866, Task 91-03, ' Technical Assistance in the Support of the Determination of Particulate Sample Line Loss at Browns Ferry, Unit 2" NRC TAC:80018 h y Mr. West:
This le*.ter report constitutes the final report for Task Assignment 91-03.
The objective of this task is to assist the NRC in assessing the adequacy of various systems for sampling particulates at Browns Ferry, Unit 2.
Specifi.
cally, this task looked at the air sampling systems for the reactor building, turbine bulding and refuel floor ventilation exhausts.
BACKGROUND A region 1: inspection of the Browns Ferry Nuclear Plant identified sample lines entering the constant air monitors of the reactor building, turbine building and refuel floor ventilation exhausts as having several new right angle bends prior to entering the sample collectors. These configurations raised questions as to whether the sample lines met the criteria of Appendix B of ANSI N13.1-1969, " Particle Deposition in sample Lines, Guide to Sampling Airborne Radioactive Materials in Nuclear facilities."
CONCLUSIONS The air sample transport tubes installed by the licensee and furnished by the CAM vendor would appear to be adequate if one accepts the licensee's propo-sition that particle sizes under sampler operating conditions will remain no larger than a couple of microns.
If the airborne particles include substan-tial mass on particles larger than a few microns, then the sampler transport tubing would significantly hinder sample delivery. The licensee has stated that fuel integrity is excellent and that maintenance work in the areas served by these ventilation systems is conducted in temporary enclosures with inde-pendent HEPA filter systems. The licensee also stated tnat attempts to 7-ow., a --
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C8BaHeHe Mr. K. Steven West September 6, 1991 Page 2 collect psrticle size data have been frustrated by the low levels of activity.
Therefore, the licensee's particle size assumption seems plausible, but remains unconfirmed.
It was further concluced that there was no data to rationalize the use of single nozzle sampling probes in the large ducts; however, the probes are scheduled for replacemer.t with improved designs shortly.
Suggestions for validating the performance of the new probes were given.
DJSCUS$10N The details of this assessment will be discussed in three parts:
Sample Transport Tubing; Sample Extraction Probe; and Eberline Model 250 CAM.
Samole Trans M rt Tubina The transport tubing is the part of the sampling system piping that conveys the sampled particles from the probe to the collection filter.
Obtaining adequate information for this assessment required a plant trip to personally inspect and measure the system components.
Tables 1, 2, and 3 list the description of each tubing segment of each air sampler in order from the tip of the probe nozzle to the CAM filter holder.
Figures 1 through 4 are simplified sketches of the systems.
Sources of infor-mation included field observations and TVA Browns Ferry Special Tests ST 8701 (Mims 1987) and ST 8815 and Drawings:
47W600 80 for probe detaih; W1073117 for details adjacent to the CAM; and 47W928 Sheets 1 through 5 for the eleva-tions.
Precise information on the wall thicknesses of the flexible tubes and the tubes in the CAM was lacking so values were assumed. The sags in the flexible tubes were considered of minor importance and are ignored.
A 2-cm radius for the e'50ws was assumed (although the value is unnecessary for most models of bend losses) to subtract from the corner-to-corner length in calcu-lating tube runs. Fittings, valves, and water traps were assumed to have the same inside diameter as the connecting tubes. Models for particle losses due to brief abrupt diameter changes are not available anyway.
Tables 4, 5 and 6 summarize the piping runs fur each sampler to make model input simpler. The subtotal length of similar tube runs is given.
Similar bends are grouped together.
The total number of bends and the total run length of each group of bends is given. The total length of the entire sample transport route is estimated.
Curths (1991) used longer tube runs and fewer bends in his analysis as shown at the end of each table.
Table 7 lists key operating parameters for each sampling syster..
References used for the data include TVA Browns Ferry Technical Instruction TI-15 Revision 6 (Nix 1991) and field observations. The sampler flows are based on field observations at the CAM which reads in mass units (scfm): 0.77, 1.77, 1.55 scfm for the turbine building, refuel floor and reactor building samplers
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y, OBattelle Mr. K. Steven West September 6, 1991 Page 3 respectively. Actual volumetric flow at the nozzle will vary in proportion to the absolute air temperature. The air temperature in the ducts probably ranges from 70'F to 110'F. so the volumetric flow at the nozzle could be about (570/530-)1.08 times higher than the reading at the assumed maximum tempera-ture.
The data for air flow in the ducts were assumed to be in terms of actual volumetric flow.
Duct flows at low fan speed are from T! 15 page 26.
At high fan speed, duct flows are from TI 15, page 17, the column for actual measurements.
Table 8 shows the estimated fractional particle penetration through each sampler as a function of particle aerodynamic diameter (unity density spheres) using the model developed by Wong, et. al. (1991)3 The results are for particles of single size. Mixtures of sizes can also be run if desired.
The conditions modelled were those itsted in Table 7 for the low duct flow at 70'F.
The other conditions can also be run if desired.
At higher tempern-ture, the disparity between intake and duct air velocity would be larger yielding worse penetration values. At higher duct flow, the disparity is reduced, yielding improved penetration.
The air sample transport tubes would appear to be adequate if one accepts the licensee's proposition that particle sizes under sampler operating ccnditions will remain no larger than a couple of microns, if the airborne particle included substantial mass on particles larger than a few microns, then the sampler transport tubing would significantly hinder sample delivery.
The licensee has stated that fuel integrity is excellent and that maintenance work in the parts of the plant served by these ventilation systems is conducted in temporary enclosures with independent HEPA filter systems.
They have also stated that attempts to collect particle size data have been frustrated by the low levels of activity.
Samole Extraction Probe The probe locations, although not in keeping with ANSI N13.1 recommendations, are about as good as available with the existing ductwork.
There is no par-ticle concentration mapping data in the sampled cross sections of the ducts to rationalize the use of a single nozzle probo instead of several nozzles across the duct cross section.
Perhaps with the small expected particle size, the particles are well mixed in the air flow. Generally, the probes are located too near a change in a direction flow.
If contaminant comes mostly from one of the feeder ducts in the Reactor Building vuct for example, it may not be well mixed with the bulk air flow by the time it reaches the sampling nozzle pl ane.
This is a common failing of air sampling systems.
Because particle I
Wong F.S., N.K. Anand and A.R. McFarland. April 1991. Software Program for Characterizino Aerosol Penetntjon Throuah Transofrt Systems.
NRC Cortract Grant NRC 04 89 353 (monitored by Stephen A. McGuire), Texas A&M University.
t Mr. K. Steven West 4%8BaMR September 6, 1991 Page 4 l
mapping data cannot be obtained and because the probe will be replaced with a multi nozzle probe, further consideration is not given to this topic.
It is suggested that the licensee conduct contaminant mapping when probe replacement provides the opportunity.
Eberline Model 250 CAM The manufacturer did not provide data on particle penetration through their CAM piping.
However, that piping has been modified by the licensee and particle penetration was estimated as detailed above. The liberal use of a variety of pipe fittings and size changes would seem to bode ill for particle penetration.
DNAL COMMENTS The documentation available from the licensee was incomslete and should be updated, especially when the new probe is installed.
Taeir assessment of the system adequacy, while in close agreement with this assessment for small particles, was deficient in terms of the equipment description.
The system adequacy owes more to the small presumed size of the contaminant particles than to thoughtful design and implementation practices.
Sincerely, b
<bMf John A. Glissmeyer Senior Research Engineer Applied Meteorology ATMOSPHERIC SCIENCES DEPARTMENT JAG:rak Enclosures cc: Jack Hayes Brian Thomas l
1 l
REFERENCED TVA SUBMITTALS Curths, D. W.
January 3, 1991.
" Browns ferry Nuclear Plant (BFN)
Airborne Sample Line Interim Plateout Evaluation - Eberline Continuous Monitors and GE Stack Monitor."
In Memorandum to J. W. Sabados, Chemistry Technical Support Supervisor, PKA lE BFN, lennessee Valley Authority, Knoxville, Tennessee.
Hims, D. C.
June 24, 1987.
" Browns ferry Nuclear Plant (BFN)
Duct Velocity and Probe Dimensions - Special Test.8701."
In Memorandum to Plant Operations Review Comittee, Tennessee Valley Authority, Knoxville, Tennessee.
Nix, D.
June 27, 1991.
" Radioactive Gaseous Effluent Engineering Calcula-tions and Measurements, Procedure 0 T1 15 Rev 6.'
Browns ferry Nuclear Plant, Tennessee Valley Authority, Knoxville, Tennessee.
ST 8815 Ventilation Flow Heasurements 2 250 CAM Monitoring System Technical Manual. Eberline, Santa Fe, New Mexico.
Browns ferry Drawings:
47W600 80, Mechanical Instruments and Controls W1073 ll7, Powerhouse Unit 2 Mechanical Instruments and Controls 47W928 Sheets 1 - 5, Hechanical Heating and Ventilating Framing Details
Table 1.
Reatt0r Sarpier Tubing Details teferences (F.C. denotes insi de field Othmeter Length or lepment De se r t pt ion observation) kat erial em factus en 1
6:2;1e vertical li 8701 lli C.573 9
47vt00 80 t
herrie vertical 1* 00 $5T 0.049 2.29 14 411 3
tettle 908 fend 30 10 4
herrie Heriront:1 5
Hortrontal F.O.
?$
6 00' fend 30 7
Heriteetal fB 6
90' Bend 30 9
herirectal 99 10 90' tend 30 11 Herirontai 106 12 90' 6end 30
,eriteata) 325 13 14 Hortrental V1073 ll?
19 15 90' Beed F0 10 16 Herirontal
- " & Water itap 55 17 3' to heriter.tal 1* lli Fles 97 L
Tute & Fittings V1073-117 16 90' Elbow V1073-11_7 (1 bow
?
19 Horizontal l'
OD $$T 53 Valve &
Fittings 20 korizontal in CAM F.C. L Yendor l'
00 151 38 Diagram Yalve &
Fittings 21 Hortrontal in CAM L' 00 15T 0.049 1.02 28 mall & Fit. tings.
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Table 2.
Refuel Sampler Tubing Details l
l'a fe rences lF.C. denotes inside I
fleid Olputer length or Se; rent Desertrttoe, octervation)
Material en taalus en 1
her:1e Vertical
$1 8701
$$1 0 to 9
47vt0D 80 t
her:1e Vertical la DD $110.049 f.29 11 mall 3
her:1e 90' Benc 30 4
h:stle Mettrerital 46 Hertrental F.0.
39 6
90' tens 30 7
vertical F.0 L 47v928 5 (18 e
90' tend F0 30 9
Hertrental 955 10 90' Bend 30 11 vertical (59 12 90' feed 30 13 hertrental
!!?
14 hertronta)
V1073 117
)$
15 90* [1be.
2 16 Hertrental
& Veter Trap 37 17 90' E$ bow 1* Fitting 2
18 25' to Horizontal F.C.
l' $$1 Flex 110 Tube & Fittings 19 90' [1 bon (1 bow
?
20 Hertrontal 1*
00 $$T
!9 Valve &
Fittings 21 Horizontal in CM F.0. L vendor 1*
OD $$i 23 Otagram Valve L Fittings it Hortrontal in CM 4 00 $$T 0.049 1.02 43 L
.all & Fittings
I lable 3.
Turbine Sartpler Tubing Details References (F.O. denotes inside field Diameter length er Se; rent De sc ript ion ot>tersa t ion)
Katerial cn Radtus ca 1
heille nattical
$1 8701 5!T 0.100 47 600 10 2
bcztle Vertical 1* CD 151 0. c4 9 2.29 13 mail 30 3
hetzte 90' fend 4
ker:1e herisental 46 Hortteatal F.C.
30 6
90' f er>d 30 7
verticai tit 30 3
9t* Eend 9
Herticetal 315 10 90' fand 30 (19 11 Vertical 12
$0* Beed 30 90' feed 30 13 14 Moritental 162 1$
heetrental W1073-117 82 16 90' (1 bow 1* Fittir'g 2
17 Mcriaontal l' 00 ill L t!
Vater Trop 18 90' Elbow l' Fitting 2
19 31' to Hortiontal F.C.
1* 151 Flex
$8 Tube & Fitttogs 20 90' Elbow V1073 117 (Ibe.
2 21 Horirontal l'
00 $51 37 valve &
Fittings 22 Hortrontal in CM F.O. & Venoor l'
OD $5T 18 Diagram Valve &
Fittings 23 Hortiontal in CM P 00 $1T 0.049 1.02 48 mall & Fittings _j
yc La111. 4_,.
Reactor Sampler lubing Consolidated Type Segments ID, em Length, cm Radius, cm Vertical 1
0.673 9
Vertical 2
2.29 14 Horizontal 4,5,7,9, 2.29 920 11, 13, 14, s
16, 19, 20 Herizental 21 1.02 28 3' to 17 2.29 97 Horizontal 90*Eend 3, 6, 8, 10, 2.29 236 30 12 90?B;end 15 2.29 16 10 90* Bend 18 2.29 3
2 Apy oximate Total length, cm 1,323 Curths (1991) used 1616 cm horizontal, 5 90' bends, 2 45' t' ends, 2.29 cm 10 litble S t Refuel Sampler Tubing Consolidated Type segments ID, em Length, em Radius, em Vertical 1
0.80 9
Vertical 2, 7, 11 2.29 1288 Horizontal 4, 5, 9, 13 2.29 1377 14, 16, 20, 21 Horizontal 22 1.02 43 25' to 18 2.29 110 Hori2ontal 90* Bend 3, 6, 8, 10, 2.29 236 30 12 90* Elbow 15, 17, 19 2.29 9
2 Approximate Total length, em 3,072 Curths (1991) used 2012 cm horizontal,1585 cm vertical, 6-90* bends,1-45' bend 2.29 cm ID
Igble.6,. Turbine Sampler Tubing Consolidated Type Se9ments ID, em Length, em Radius, em Vertical 1
0.508 9
Vertical 2, 7. 11 2.29 1290 Horizontal 4, 5, 9, 14, 2.29 742 15, 17, 21, 22 Horizontal 23 1.02 48 31' to 19 2.29 98 Horizontal 90* Bend 3, 6, 8, 10, 2.29 283 30 12, 13 90* Elbow 16, 18, 20 2.29 9
2 Approximate Total length, cm 2,479 Curths (1991) used 1372 cm horizontal,1585 cm vertical, 7 90' bends,1-45' bends Table 7.
Sampler and Duct flow Parameters Parameter Reactor Refuel Turbine Sampler flow, 43.9 50.1 21.8 sipm Nozzle ID, cm 0.6731 0.8001 0.5080 Nozzle intake 20.56 16.61 17.33 velocity, m/s Ductcrosy 3.9019 2.3226 4.6451 section m low flow m'/s 20.469 9.3458 22.915 Low velocity m/s 5.25 4.02 4.93 3
High flow m /s 43.8 19.7 44.2 l
_Highvelocitym]s 11.23 8.48 9.52 l
l a
Table 8.
Fractional Penetration of Particles Through Each Sampler Line as a Function of Particle Aerodynamic Diameter (microns)
REACTOR Penetration for Particle Aerodynamic Diameter, microns Tube ID 1
2 5
10 20
.673 cm 0.9960 0.9815 0.7583 0.4659 0.2883 2.29 cm 0.9803 0.9303 0.6509 0.1839 0.0011 1.02 cm 0.9998 0.9992 0.9856 0.7259 0.2466 Total 0.9762 0.9124 0.4865 0.0622 0.0001 I
REFUEL Penetration for Particle Aerodynamic Diameter, microns Tube ID 1
2 5
10 20
.673 cm 0.9975 0.9890 0.8638 0.5264 0.3612 2.29 cm 0.9734 0.9104 0.5744 0.1105 0.0001 1.02 cm 0.9997 0.9987 0.9653 0.5246 0.1785 Total 0.9707 0.8992 0.4790 0.0305 0.0000 TURBINE Penetration for Aerodynamic Particle Diameter, microns Tube 10 1
2 5
10 20
.673 cm 0.9952 0.9785 0.7314 0.2895 0.1987 2.29 cm 0.9752 0.9162 0.5969 0.1313 0.0003 1.02 cm 0.9995 0.9982 0.9885 0.9408 0.4945 Total 0.9700 0.8949 0.4316 0.0358 0.0000
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Sketch of Turbine Duct Air Sampling Tubing
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