ML20058L229

Liquid Level Monitoring W/Emus More than Just Measuring Liquid Levels

ML20058L229
Person / Time
Site:	05200001
Issue date:	12/14/1993
From:	SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER
To:
Shared Package
ML20058L206	List: ML20058L204 ML20058L209 ML20058L216 ML20058L229
References
NUDOCS 9312160193
Download: ML20058L229 (10)

Text

- - _

.SIEMENS i

l

(

l I

l

_icuic

_ eve Voni:oring wi: 1EV S

l Vore :lan <us: Veasuring _icuic _ eve s l

f i

i 4

. -.4 i

{

The uitrasonic signa!s generated witn EMUS also provide clear anc re!'able information on the concition of te medium.

l t

I i

I l

I h

9312160193 931214 I"

i PDR ADOCK 05200001 i

A PDR A y,,,,,

e.,... a n. o~.,., conor.*nn arrvin j

I i

- Liquid Level Monitoring with EMUS -

l More than Just Measuring Liquid Levels l

l The Measuring Principle Installation By superposing a static magnetic EMUSin Brief Installation of the sensor is quite field on an electromagnebc high-EMUS enaoles direct monitor-simple: A permanent magnet keeps frequency field, transverse ultrasonic ing of hauid levels without the the sensor firmly attached to the waves are generated in the vessel or need to interpretindirectindica-vessef or prpe wall without the need tions; the signalimage generated for pnor treatment of the wall's pipe wall as a resuit of the mechanisms of Lorentz force, I

with EMUS provides clear surface (in the case of nonmagnetic magnetic force ano magnetostriction.

iniormation on liquidlevels.

matenals another equally simple There is consecuently no need for Contact with the medium is not method of attachment can De used).

the couplant which is customanly p

necessary.

required in ultrasonic testing.

)

EMUS can therefore be used for measurements in vessets/ tanks j

and piping carrying aggressive.

l racioactive or toxic liquias, or I

whent.1e vesselintenor is not i

accessible.

But EMUS can do mucn more j

than measure liquid tevets:

O EMUS estabhshes whether-the medium isliquid or gaseous or whetner it is a mixture.

i O inoicatesthe boundarylayer between liquid and gaseous phases, between fluids of varying density and between fluios and floating layers.

O EMUSmeasuresthethick-j ness of seoiments.

O detects floating particles and O indicateswhenliquidsstart l

to boil.

1 Production crototyhe.

eiectromCs tested with a f

Cut-Out 018 fea::tOf pressure I

vessel wellin Contact with air.

air / water fntKlute 400 water.

j i

l

1 l

i l

How EMUS Works v

a*

outse Retiector if only licuid is present in the instru-mented section. the u!!rasonic j

uaves are partly reflected on the i

l 4nside wall of the vessel and Dartly

^

l Oecoupled into the liquid. The de-q coupleo ultrasonic waves are re-l g

flected by the next reflector (see q

g Atw graphic opposite) and then picked

=

i up by a receiver R1 on the outside i

wall of the vesset. The sound waves attency reflected on the inside wait t

l cf the vessel are reflected again on q

ine outside wall and likewise plCKed up Dy R1; after further reflections l

they are ultimately picked up by R2.

Since part of the sound energy Ib 0:ss: pates into the licuid with eacn reflect:on (and is thus not Dicked

~ ~,

up), inere is a d;fference between k

the signal amptitudes formed in R1 l

Liquid / gas mixture and R2.

With a liouid/ gas mixture in the l

.nstrumented section the sound

.m waves are also partty reflectec on 1

the insice wall of the vessel. partly decoupled as longitudinal waves into

~

the mixture, wnere they are however I

campec to such an extent that no etno is received from the mixture.

Thus the echo caused in a pure houid by the sound waves decoupled into the licuid is not produced - and 3,.

this is a clear indication of a licuid/

gas mixture.

j if only gas is present in the in-J strumented section all of the ul-l l

trasonic waves are reflected on the

.nsice wall of the vessel. In this case the signats received by R1 and R2 are almost of identical amplitude.

j in oriet: The cifference between thr-s: gnats receivec by two ultrasonc y

receivers and the presence or absence of a th:rd signal indicate unetner a tiquid, mixture or gas is present.

I k

l 1

3

. ~. _

1 l

j_

l l

I e+ *; s,,e - -r*

Opg.,

%... m.

' " r -

..y. -_,-

~.gm-vire h..

i

.g d

t l

\\

E 6~ '

4 l_

?

1 4

l The reactor pressure vessels of Guncremmingen Units B ano C (FRG) whether first to be comppec with EMUS system.

I For further cetails and information on this measunng tecnnique please contact:

Siernens AG Bereicn Energieerzeugung KWU E224 Seligenstaater StraBe D-8757 Karlstein j

Telephone: (6188) 7 80-302 l

\\

Pubt:shed Dy ano copyrignt (1991):

l Siemens AG I

Bereien Energieerzeugung tKWU)

HammerbacherstraBe 12 + 14, Postfaen 3220 sot,,.ci to en.noe wereut ro e' D-B520 Erlangen o,ae,.u assimussr-a20id * ~

t e' -

i November 22, 1993 T0:

Tim Collins l

From:

Georg j mas / Amy Cubbage

{

SUBJECT:

Siemens Liquid Level Monitoring with EMUS We had the telephone conference with Dr. Slegers of Siemens (Germany) on 19th of Nov, 1993. Our questions and a summary of his response is given below:

d (1) How long has the EMUS system been in service?

f Response: The system is in service for 3 years. in KRB units' B and.'C' (Gundernmingen units).

(2) Is it used for indication only, or are there automatic functions associated with it?

i Response: It is only a single channel system and used for indication in~ control room only. The instrument monitors four levels in the reactor: low low level, high level, and two monitors one tenth of a meter above and below normal RPV.-

l level. After qualification, three channels will be installed and will be used l

for scram and ECCS actuation with 2 out of 3 logic. They plan to have automatic.

action by the end of 1994.

l (3) Has the operating. experience been satisfactory?.

Have you experienced operational or maintenance problems?

Response: The instrument was accepted by the utility in'1990 as a viable system.

The instrument is tes+ed every month.

Other utilities are-also; expected to install these soon, once the instruments are qualified. No serious maintenance

,i problems were reported.

1 (4) Were the devices backfit to the units, or were they part of the original design?

Response: They were backfitted and they were not there in the original design.

Utility installed these instruments voluntarily.

There was.no regulatory i

requirement.

(5) Are you aware of other nuclear power plants using the system in Germany or i

el sewhere?

Response: This system is in service only in the two KRB units.

l (6) How is the system used in emergency procedures? Is it only a backup to other j

level measurement systems?

q 1

I 1

I Response: They are not used in the emergency procedures. They are used by the operator during transients for backup indication.

i l

(7) Is the systam powered by emergency power supplies?

Response: No. But later, they will be supplied from emergency power supplies.

(81 Is it qualified for conditions expected after a design basis accident? After a savere accident?

Response. No. But later, they will be qualified for DBA conditions. Qualifying for severe accident is a policy issue and they are not sure of the policy. They plan to complete the qualification program this year.

(9) Are redundant and independent channels used?

Response: Three channels will be used. Hence, they will be redundant and independent.

CC. A.Thadani R. Jones M.Chiramal A.Cubbage SRXB R/F GThomas R/F 1

l l

1 i

l

p orc 4 3

E UNITED STATES I

5' NUCLEAR REGULATORY COMMISSION k....+,/

wAssiwavow, o.c. rosss-oooi T0:

Bjorn Dufva Co-ordinator, International Affairs Swedish Nuclear Power Inspectorate FROM:

Amy E. Cubbage i

Reactor Systems Engineer, Division of Systems Safety and Analysis U.S. Nuclear Regulatory Commission

SUBJECT:

QUESTIONS CONCERNING DIVERSE REACTOR VESSEL WATER LEVEL i

INSTRUMENTATION IN USE AT SWEDISH BWRS Greetings, I would like to thank you for organizing our successful meeting on October 29, November 1 and November 2, 1993.

In follow up to our meeting, we are interested in obtaining additional information on the diverse methods of determining BWR reactor vessel water level that are currently in use in Sweden. During our meeting, we learned that diverse level instrumentation sy::tems are in use at Barsebeck (core cooling monitor) for indications purposes and at Ringhals I and Oskarsham 1 (float switches) for indication and automatic functions. We are particularly interested in additional information on the following:

j (1)

It is our understanding that the core cooling monitor (BCCM) has been in use at Barsebeck for 5 years.

Is this at Barsebeck unit 1, unit 2, or both? It is also our understanding that BCCM uses heated junction thermocouples located in spare neutron monitoring locations, is this correct?

i (2)

How long have the float switches been in use at Ringhals 1 and

[

Oskarsham I? Could you provide a discussion on the design and operation of float switches?

(3)

What has the experience been with BCCM and the float switches? Have there been any operational or maintenance problems? Are they tested regularly?

(4)

What is the range of BCCM and the float switches? Is the range continuous? If not, how many detectors are installed per channel, and where are they located axially? How many channels are installed?

(5)

Is the indication provided by diverse instrumentation incorporated into.

the plant emergency procedures?

(7)

What automatic functions are provided by the float switches? Are l

redundant and independent channels used? Are they powered by emergency power supplies? Are they qualified for accident conditions?

(8)

What testing or qualification was performed on these devices prior to installation?

i r

j

)

Could you provide a technical contact' at SKI, ABB or at ths applicable plants who would be able to discuss these questions by telephone during the comingL week (December 6-9).

Please contact me to set up a time that is convenient.

for you and the appropriate. contact (s) to have a telephone call..My telephone 1 number is 1-301-504-2875, or if you would'like to send:any. information:by fax, my number is 1-301-504-3577.

i 1 appreciate your assistance.

l':

S cerely, Im/

1 yE Cubbage i

i i

i r

b

~!

j i

1 1

u

TELEFAX 1993-12-07 Datum /date Tillho Ms Amy Cubbage TLFX No.

Oddbj5rn Sandervag y,

_ Antal sidor Inkt denna No. of pages incl. this one Dear Ms Cubbage gg$$fgg Here come some answers to the questions on level measurements in your telefax of Dec 3.

1. The BCCM was not used continuously in Barsebuck. Two monitors 4

were installed in the Barsebuck 1 reactor in September 88. The objective was to obtain a long term test in a reactor. There were some problems with vibrations which caused damage to the cable connections. A BCCM m

with modified design was therefore installed in 1989. This monitor was taken out after two years for control. Since then no monitors have been present in the reactor. The utility has taken a decision to install BCCM permanently in the Barsebsck reactors.

v The BCCMs do not use heated junction thermocouples. It is in principle a resistance thermometer. This is an important features of the equipment since it gives much higher output signai. The BCCMs are used in two modes; one as a cooling monitor and one as a temperature measurement.

2. The float switches have been used from start of operation,1972-1974. A floating body is connected to a micro-switch. When the water level passes tne floating body, it moves and activates the micro-switch.

Pouness-Ponaladdnss 0anadress-OfSce Telefon Telephone Telegrarn Cable Telex Box 27106 Schinedtsgatan 11

+46-8 665 44 60 SWEDATOM.Stockhohn 119 61 Telefax 5 102 52 STOCKHOLM

+46-8 661 90 86

3. The experience with the floating switches is good. There were some initial problems, but these could quickly be resolved. They are tested every year. Testing can only be made when the reactor is in shutdown.

They are tested by injecting nitrogen which simulates the level change.

4. The range of both BCCM and the float switches is discrete which means that they produce a signal when the level passes the elevation where they are located. Typically BCCMs are installed at four axial locations (top, middle and bottom of the core, and near the vessel bottom). The float switches are typcally located at three levels in the vessel; 4 or 6 at each level. The total number in the vessel is thus 12 (Oskarshamn 1) or 18 (Ringhals 1). Fioat switches are used also in many "other vessels at the sites as well.

5. The signals from the float switches are used in the EOPs. Use of the j

switches is incorporated in the operator emergency training.

j

7. The indications from the float switches will cause reactor scram on low level (2 of 4 logic in Oskarshamn 1,4 of 6 in Ringhals 1). At very low level they willinitiate isolation signal and start safety injection. At extremely low levels, they will automatically activate the automatic depressurization system. The float switches are powered by emergency power (D/C from batteries). They have been qualified for accident conditions.

8. It is very long ago the float switches were taken into use, so it Is difficult to exactly verify which qualification they have gone through. The equipment has earlier widely been used also outside the nuclear applica-tions. The BCCM has been tested in two-phase loops at the University and also in Barsebsck. It is considered qualified.

For further contacts you need, please contact Hans Eriksson, SKI (+ 46 8 6654400) or myself (I am not in the office on Thursday and Friday). For details of the BCCM in-pile testing you may contact Ole Gr6ndalen, Barsebhck (+ 46 40 255000).

i Y

OY$

Vnst A

an

-