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Accession #: D196071688

Document #: SD-WM-CDR-026

TitlelDesc: ENGINEERING STUDY & CONCEPTUAL DESIGN REPORT FOR PRIMARY VENTILATION DUCT FLOW MONITORING

WHC-SD-WM-COR-026 . REV 0

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TABLE OF CONTENTS

OBJECTIVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 .1 BACKGROUND AND SCOPE . . . . . . . . . . . . . . . . . . . . . 1 . 2 PURPOSE AND NEE0 . . . . . . . . . . . . . . . . . . . . . . .

SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RECOMMENDATION AND CONCLUSIONS . . . . . . . . . . . . . . . . . . . 3.1 RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . 3.2 CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . .

UNCERTAINTIES . . . . . . . . . . . . . . . . . . . . . . . . . . . DESCRIPTION OF ALTERNATIVES AND SOLUTIONS . . . . . . . . . . . . .

5 .1 CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . 2 ASSUMPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 ALTERNATIVES . . . . . . . . . . . . . . . . . . . . . . . . .

DISCUSSION OF PREFERRED ALTERNATIVE/SOLUTION . . . . . . . . . . . . NO ACTION ALTERNATIVE . . . . . . . . . . . . . . . . . . . . . . . BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPENDICES . . . . . . . . . . . . . . . .

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LIST OF ACRONYMS AND ABBREVIATIONS

Constant Power Anemometer Constant Temperature Anemometer Double Shel l Tank

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ENGINEERING STUDY AND CONCEPTUAL DESIGN REPORT FOR PRIMARY VENTILATION DUCT FLOW MONITORING

1.0 OBJECTIVE

The objective of this engineering study is to develop the preferred method and concepts for measurement of the primary exhaust ventilation flow rates in Double Shell Tanks (DSTs) on the hydrogen watch list. tanks lOl-AW, 103, 104, and 105-AN, 103-SY. A systems engineering approach is utilized to weigh the desired characteristics of the flow monitoring system, and then select the best alternative.

This includes

1.1 BACKGROUND AND SCOPE

Accurate air flow measurement at the low flow rates existing in these vent ducts is quite difficult. flowmeters on the market that makes selecting an appropriate flowmeter a complex and potentially difficult task. various characteristics such as accuracy, response time, range, cost, and maintainability are necessary in order to select the flowmeter that best meets the needs for a given application.

In addition, there is a wide variety of

Trade-offs in performance among the

Measurement of air flow in these 30.48 cm (12 inch) diameter ducts This greatly involves instrumentation that is intrusive into the ducts.

increases the cost of installing, maintaining and calibrating the instrument as these ducts are radiologically contaminated. Since these tanks are on the hydrogen watch list there are additional requirements that will also increase these costs.

1.2 PURPOSE AND NEED

with hydrogen monitoring equipment already installed, it will allow for determination of the overall hydrogen generation and release rates. This information will assist in evaluating ventilation system effectiveness in resolving hydrogen safety issues. with draft Systems Engineering Requirement WHC-SD-WM-OSR-16.R.OA.SEC.5.29 which states in part:

The purpose of flow monitoring for these tanks is that in conjunction

This work is to be done in order to comply

"Administrative controls shall be established to manage flammable gas hazards related to the waste storage tanks that generate flammable gasses. The administrative controls shall include not only tanks in which waste exhibits the potential to retain flammable gasses and release them episodically but also tanks in which waste generates and

include as a minimum: . releases flammable gasses chronically. The program elements shall

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a. Flammable gas generation rates and ventilation effectiveness, as well as tank physical parameter information (e.g. waste level, pressure, temperature), shall be evaluated and compared with established criteria to (1) assign the proper NFPA classifications and (2) identify tanks in which waste exhibits the potential to retain flammable gases and release them episodically and thus comprise the Flammable Gas Watch List."

2.0 SUMMARY

Several types of flow monitors were investigated and determined whether Based on their performance, some were they were useful for this application.

selected for further evaluation, and were evaluated against each other to find the one which offered the best performance at the lowest initial and operating cost. The selected, i.e. the preferred, unit was found to be the Sierra Series 640 Steel-Trak". frgm 1.5 to 107 m/min (5-350 fpm) or air flow rates of 0.1 to 7.8 m (4-275 ft ) per minute direct without any conversion, and it is approved for Class I, Division I, Group B, C, and D,.service. traverse type differential pressure element coupled with a high accuracy pressure transmitter (POT) to monitor the flow velocity. This unit was found to be marginal if not incapable to peasure the 12.2 m/min (40 fpm) air velocity, i.e. the 2.5E-3 Pa (1x10- inches of water) differential pressure. It further required the temperature of the vapor stream, and computations from the data, to calculate the air flow. To execute these calculations, (to derive the air mass flow from the temperature and the differential pressure data), would require an additional programmable controller or some other compatible device.

This unit is capable of measuring air velo:ities

The other possible selection is the

3.0 RECOMMENDATION AND CONCLUSIONS

3.1 RECOMMENDATIONS

The preferred, unit was determined to be the Sierra Series 640 Steel- TrakTn. This unit is capable in measuring air velocities from 5 fpm to 350 fpm, or air flow rates of 0.1 to 7.8 m (4-275 ft ) per minute direct without any conversion, in single range or up to 3.3E m (10,000 ft) per minute, in multiple ranges. air velocity direct, without additional data or hardware. It can operate between 7.2 and 35 "C (45-95'F) without any degradation of accuracy, or 4.4 and 65 "C (40-150°F) with minimal loss of accuracy. It is approved for Class I, Division I, Group B, C, and D, service. It has a 4 ma to 20 ma output which is directly compatible with the Tank Monitoring and Control System, (TMACS), and it is supplied with 15.2 m (50 ft) of cable, as a plus it can have a local digital Liquid Crystal Display, LCD. It is reasonably priced at

It can be calibrated to read and display either mass flow or

' A trademark of Sierra Instruments Inc, Monterey, California

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5.2 ASSUMPTIONS

Selections of the instrument to be used, is made by this Engineering Study and Conceptual Design document.

5.3 ALTERNATIVES

There is a wide array of flow monitoring technologies that might be applicable to use in these vent ducts. identify alternatives and then narrow down the field was: commercially available flow monitoring technologies developed. 2) The list was then narrowed down to those technologies that were applicable, based on use in low flow velocity air. 3) A list of various models was developed for comparison to the design requirements. 4) Two or three models from the list that most closely meet the design requirements were compared by developing a conceptual installation design, and discussing the pros and cons of each model.

5.3.1 Selection o f Flow Monitoring Technologies

whether they would be viable for this application.

The approach that was taken to 1) A list of

The following flow monitoring technologies were investigated as to

Magnetic Flow Meters Vortex Shedding Flow Meters Coriolis Mass Flow Meters Thermal Mass Flow Meters Turbine Flow Meters Differential Pressure Flow Elements (e.g. flow orifice, pitot tube, flow traverse probe, venturi nozzle, etc.) Ultrasonic Time o f Flight Flow Meters Ultrasonic Doppler Flow Meters

From this list, two technologies were quickly identified as having the best potential for use in this application. Thermal Mass Flow Meters (also known as thermal anemometers), and the flow traverse probe with a pressure transducer and square root extractor. others were dismissed for the following reasons.

Maqnetic Flow Meters

The two technologies are the

The

Magnetic flow meters are not designed for use in gases or vapors.

Vortex Sheddinq Flow Meters

met in this application under all conditions. were capable of monitoring at this low a flow rate.

Require a Reynolds number of >10,000 for linear operation, which is not No models were identified that

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Coriolis Mass Flow Meters

up to 15 cm (6 inches) in diameter only. Not typically used for gases and vapors. Typically available for ducts

Turbine Flow Meters

Typically unable to measure flow at this low of a velocity.

Differential Pressure Elements

With the exception of the flow traverse probe and the pitot tube, installation of other types of flow elements in the duct (which i s made of standard schedule carbon steel pipe) is thought to be too difficult and costly. Installation of an orifice or nozzle would require removal of a section of the duct and welding in flanges for a new spool piece.

Ultrasonic Time o f Fliclht

over thermal mass flow or the flow traverse probe. duct i s considerably more difficult and requires twice the number of penetrations.

Ultrasonic DODDler

Applicable for this application, but clearly offers no further benefits Installation in the vent

Not designed for use in gases and vapors.

5.3.2 Description o f Applicable Technologies

5.3.2.1 Thermal Mass Flow Meters There are two basic types of thermal convection mass flow sensors in general use today:

a) Constant Power Anemometer (CPA) b) Constant Temperature Anemometer (CTA)

Both operate on the same premise that a heated element inserted into the fluid stream will develop a temperature differential between it and the fluid stream due to convective losses. These convective losses are proportional to the square root of the flow velocity. temperature of the fluid and the heated element is incorporated into the design of the sensor.

A means of measuring the ambient

A CPA provides a fixed electrical power to a resistance element. The difference between the temperature of the heated element and the ambient fluid temperature is measured. velocities and decreases with increasing flow velocities. difference is conditioned to be linear with the mass velocity.

The temperature difference is large at low flow The temperature

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TAB1 I,

Instrument Type* Range ( f t /min )

Accuracy

II I I I

MC Veltron 720012 with a Volu-Probe 4SS

FCI LT8lA

40-400 t0.45X FS

i3% reading

FCI M T M multipoint

Kurz series 450Ex

sierra series uo STEEL-TRAK~" I CTA

ELdridge Model 8831-SSS-AIR I CTA

Thermal lnstrunent Co. d e l 59 or 62

uorth Instrunents

15-custm

20-400

5-350

15-400

?

30-400

t l % FS or t3% reading

*[1% reading + 20 SFPMl

tl% FS 40% t2X reading 10% - 100% f E% reading + 1% F S I

t 1% FS

22% reading

I I I CTA - Constant Temperature Anemometer CPA - Constant Power Anemometer FTP - Flow Traverse Probe

* Type

2

Res pons e

(seconds) Temp.

I

-SO t o 350 0 to 150 For 63.3% change: 9 sec. &creasing 15 sec. increasing

15 sec. increasin

45 to 145 -4 to 122 1

-52 to 392 32 to 122 1

-20 to 350 ? 1.5

? ? ?

FM Approval f o r Class I , D i v . 1, Group B R w i red

NO

Yes

Yes

Pending (2 months?)

Yes

Transni t t e r is . Probe unknown.

NO

1

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From t h e t a b l e i t can be seen t h a t the th ree inst ruments t h a t most nea r l y meet t h e design s p e c i f i c a t i o n are the FCI constant power anemometer, t h e S i e r r a constant temperature anemometer, and t h e A i r Mon i to r Corp. t rave rse probe and d i f f e r e n t i a l pressure t r a n s m i t t e r . The S i e r r a CTM o f f e r s t h e most c o m p a t i b i l i t y w i t h t h e design requirements i n a l l areas o f performance: safety, ease o f i n s t a l l a t i o n s , s i m p l i c i t y o f c a l i b r a t i o n and da ta r e t r i e v a l , as w e l l as reasonably low cost .

5.3.3 Conceptual Design

develop a conceptual i n s t a l l a t i o n design i n order t o compare costs , ease o r use, and ease o f maintenance. anemometers w i l l have t h e same i n s t a l l a t i o n design even though t h e minimum temperature l i s t e d f o r t h e S i e r r a instrument i s -20 "C ( -4°F) . w i t h t h e sa les rep resen ta t i ve have i n d i c a t e d t h e instrument has been t e s t e d down t o -2.3 " C (-1O'F) w i t h no adverse e f f e c t s , and t h e company f e e l s -29 " C (-20°F) should no t be a problem.

5.3.3.1 Thermal Anemometers Since bo th thermal anemometers i nc lude weather t i g h t ins t rumenta t ion t h a t can meet t h e ambient temperature c r i t e r i a no weather enclosure i s needed. The t r a n s m i t t e r can be mounted e i t h e r r i g h t a t t h e vent header w i t h t h e probe, o r remotely w i t h i n 30 m (100 f e e t ) o f t h e probe. i n c h MNPT threading. f i t t i n g as was done w i t h t h e SHMS. vent duct . a v a i l a b l e a t t h e associated SHMS cab ine t .

d iameter ho le i n t h e vent duct and then i n s t a l l t h e saddle clamp and t h e p robe / t ransmi t te r assembly on the duct . Power and s igna l w i res a re then rou ted from t h e t r a n s m i t t e r t o t h e associated SHMS cab ine t . ou tpu t s igna l (4-20 mAdc) w i l l be connected t o the s t r i p c h a r t recorder i n t h e SHMS and t o t h e TMACs cab ine t associated w i t h t h a t SHMS. I n t h e AN and AW farms t h e duc t work i s l oca ted i n a v e n t i l a t i o n p i t below grade, w h i l e i n SY farm t h e duc t work i s above grade. I n t h e v e n t i l a t i o n p i t s a small d iameter ho le w i l l need t o be d r i l l e d through t h e concrete i n o rder t o r o u t e w i r i n g i n t o t h e p i t .

I n o rder t o c a r e f u l l y evaluate t h e th ree technologies i t i s necessary t o

The constant pressure and constant temperature

Consu l ta t ion

The probe i t s e l f requ i res a 2 . 5 4 cm (1 inch) diameter opening w i t h 1 Saddle clamps w i t h a gasket w i l l be used t o p rov ide t h i s

Th is w i l l prevent having t o weld on t h e Both o f these instruments can be powered by 24 VDC which i s

E s s e n t i a l l y , a l l t h a t i s requ i red i s t o d r i l l a 2.54 cm (1 inch)

The t r a n s m i t t e r

5.3.3.2 Traverse Probe and D i f f e r e n t i a l Pressure Transmi t te r The main d i f f e r e n c e i n i n s t a l l a t i o n o f t h e t h i s op t i on i s t h a t t h e d i f f e r e n t i a l pressure t r a n s m i t t e r w i l l need t o be i n s t a l l e d i n an env i ronmenta l ly c o n t r o l l e d cab ine t as t h e e l e c t r o n i c s are on ly r a t e d from 4 t o 49 "C (40 t o 12O'F), and are no t weatherproof. cab ine t w i t h heat ing and a i r cond i t i on ing which p r e l i m i n a r y c a l c u l a t i o n s show requ i res 3-5 amps o f 240 VAC power. pad be poured.

This e n t a i l s i n s t a l l i n g a nearby

Th is cab ine t w i l l r e q u i r e t h a t a concrete

The probe i n s t a l l a t i o n w i l l r e q u i r e a 4.45 cm (1 3/4 i nch) diameter ho le

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marginal i f n o t incapable t o measure the 40 fpm a i r v e l o c i t y , i . e . t h e 1 ~ 1 0 ' ~ inches o f water d i f f e r e n t i a l pressure. Fur ther , i t requ i red t h e temperature of t h e vapor stream, and computations f rom the data, t o c a l c u l a t e t h e a i r f l ow . To d e r i v e t h e a i r mass f l o w from t h e temperature and t h e d i f f e r e n t i a l pressure data would r e q u i r e an a d d i t i o n a l programmable c o n t r o l l e r , o r some o the r compat ib le device t o compute and present useable data. Therefore, t h e concept o f us ing t h i s dev ice has been abandoned.

7.0 NO ACTION ALTERNATIVE

The no a c t i o n a l t e r n a t i v e would mean t h a t i n fo rma t ion t o perhaps take t h e tank o f f t h e hydrogen watch l i s t would n o t be ava i l ab le . Pe r iod i c da ta might be o f some use, bu t t o remove a tank from the hydrogen watch l i s t based on p e r i o d i c data would n o t stand up t o t h e c lose s c r u t i n y o f ou ts ide rev iewers. Cer ta in l y , t h e d i f f e r e n c e i n the cos t o f opera t ion o f a tank on t h e hydrogen watch l i s t versus a tank not on t h e hydrogen watch l i s t i s more than t h e cos t o f i n s t a l l a t i o n and opera t ion o f the f l o w mon i to r ing system.

8.0 BIBLIOGRAPHY

Hardy, H.E., "Flow'Meters f o r Use i n . t h e Nuclear Indus t ry : How t o Se lec t t h e Appropr ia te Instrument", CONF-910852, 1991.

Kurz, J., "Charac te r i s t i cs and App l i ca t i ons o f I n d u s t r i a l Thermal Mass Flow Transmi t ters" , Proceedings o f the 47 th Annual Symposium on Ins t rumenta t ion f o r the Process I n d u s t r i e s , 1992.

M i l l e r , R.W., Flow Measurement Engineer ing Handbook, McGraw-Hill, 1983.

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Subtotal-lnnr

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TOTAL 247100 21 4 0 52010 290970

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