ML17138A540

Rept Translated from German:Expected Values of Blowdown Tests W/Relief Sys in Non-Nuclear Hot Test at Brunsbuttel Nuclear Power Plant & Their Measurement.

ML17138A540
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Issue date:	09/30/1974
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I PROPRIETARY IN FORMATION This document has been made NON-PROPRIETARY by the deletion of that information which was classified as PROPRIETARY by KRAFTWERK UNION AG (KWU).

The PROPRIETARY information deletions are so noted throughout the report where indicated by a) Use of the term KRAFTWERK UNION AG PROPRIETARY INFORMAT ION .

b) Use of blocked out areas by cross hatch bands in the report text and figures/tables, e.g. 1 h

i) ...." with a mass flow density oflk~~1Kg/m2s...";

ii) MM~~ mm iii) ....." should be kept below WgZd~ atm."

iv) 8'/17/7 8

Offenbach/:lain 30 Se te.-..her 1974 Place Date Technical Report; KNU/R 1 - 3141 File number R 113-SD Dr. Becker . 'uthor R 113 l De artment Countersi natu" e /s!

T.i tie: Expected values of the blowdown Pages of text 19 tests with the relief system in Figures 4

'0 the non-nuclear hot test at the Circuit diagrams Brunsbut tel nuclear power plant and their measurement Diag r./oscar 1 1'ogr .

Tables Ke, words (max. 12) to identify the Reference )Iist report's conte.".=: $

Relief syste.-, perforated pipe quencher, suppression chamber, thermoh draulic loads Summary On the basis of model tests in the Grosskraftwerk Nannheim (GK<'.)

[Mannheim Central Power Stationl at a lt5 scale and in the Gross-welzheim model test stand at a 1:100 scale, detailed statements are made concerning the expected measurement values in the non-nuclear hot tests in the Brunsbuttel nuclear power plant with the actual relief system. In papticular, the statements relate to

- the behavior of the

- the thermohydraulic relief valve, loads on the relief system, the suppression chamber and its internal fittings, and

- the temperature mixing.

Parameter studies permit an immediate evaluation of the measure-ment values and make extrapolations possible. The measurement of the quantities of interest is described in detail and load-stress variations for the test evaluation are indicated.

/s/ (Dr. Becker)

/s/ (Gobel)

/s/ (Ru ) /s/ (Dr. Koch s/ (Frohlich) I 'T Author s signature Examiner Classzfier Class For zn ormatxon Distr> utzon xstt (cover sheet only): lx KWV/GA 19 Erl lx /PSN 22 Ffm Transmzsszon or dup scat>on o thzs ocument, exploztatzon or com-munication of its content not permitted unless expressly authorized.

Infringe:s liable to oay damages. All rights to the award of patents or registration of utility patents reserved.

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Distribution list (internal)

Yerteiler ((nlern)

R - ffe RZR RS 2 x RS 11 RS 1 1 5/G KT RS 1 2/KKB RS 12/KKK RS 13/Kw" RS 13/KKP RS 14/KKI RS 15 RS 2 RS 21 RS 213 R ii - ffe R 11 Er 1 R 111 2 z R 113 R 113 SD 2 L R

R 213 2 x R 314 3 x R 32 R 3 R 52 R 521 5 x R

Y 822 TA 2 x R 311 11-2

NONLIABILITYCLAUSE

'I This report is based on the current technical knowledge of KRAFTWERK UNION AG, However, KMETHERK UNION AG and all persons acting in its behalf make no guarantee. In particular, they are not liable for the correctness, accuracy and completeness of the data contained in this report nor for the observance of third-party rights.

II This reservation does not apply insofar as the report is deliverea j

in fulfillment of contractual obligations, nor with respect to licensing authorities or the experts appointed by them.

KRAFTWERK UNION AG reserves all rights to the technical information contained in this report, particularly the right to apply for patents.

Further dissemination of this report and of the knowledge con-tained therein requires the written approval of KRAFTWERK UNION AG. Moreover,, this report is conanunicated under the assumption that it will be handled confidentially.

11-3

TABLE OF CONTENTS Xntroduction 11-5

2. Opening time and flow rate of the safety/relief valve 11-7 3 ~ Internal pressure in the blowdown pipe and quenche" 11-9 3.1 Expected vent clearing pressures 11-9 3.2 Expected steady-state pressures 11-'

3 ' Measurement of the pressure 11-10 Vertical impulse force during water impulsion 11-1' Expected values of the vertical impulse 1

4.1 4,2 Measurement of the vertical impulse 11-'

4.2.1 Strain measurement on the blowdown pipe 1'12 4.2.2 Strain measurement on the restraining structure 11-'

5. Transverse force and torsional moment on the quenche" during operation 11-14 5.1 Expected values of the transverse force on a quencher a~ 11-14 5'. 2 Measurement of transverse force and torsional moment 11-15

6. Pressure at the bottom and walls of the suppression 11-18 chamber 6.1 Expected values during vent clearing 11-18 6.1.1 Maximum pressure amplitude near the quencher 11-18 6.1.2 Pressure distribution in the circumferential directio n and in the vertical center section 11-20 6.1.3 Superposition during the clearing of two quenchers 11-21 6.2 Expected values during condensation 11-23 6.3 Measurement of the pressure distribution 11-24

7. Forces on internal fittings due to relief processes 11-26

8. Temperatures 11-2g Tables Figures References

l. Introduction The start-up tests in the Kernkraftwerk Wurgassen (KWW) fWurgassen nuclear power plant ] show that large forces can be exerted on the containment by the pressure relief system. These involve air oscillations during vent clearing and the pulsations for conden-sation at high water temperatures. In a development program with model tests in the GKM at a 1:4 scale, it was possible in the summer of 1972 to achieve a reduction of the air oscillations with a lowe"-limited valve opening time and an additional pre-impingement of steam. Tests in the KWW confirm the expected bottom pressures /1,2/.

This was followed by another development phase whose aim was to reduce the air oscillations and to make the temperature limit fo" the condensation less critical, using passive measures. Litera-ture studies and screening tests in the GKM and model tank in winter of 1972/73 /3/ led in April 1973 to the choice of

'he the perforated-pipe quencher.

The essential model parameters were investigated in tests with I

a model perforated-pipe quencher. Test. results and their inter-pretations are contained in /4,5,6/.

The conclusion of the development program is to be the non-nuclear hot tests in the Kernkraftwerk Brunsbuttel {KKB) fBruns-buttel nuclear power plant] with the actual geometry . A tes=

P rogram with extensive inptrumentation was set up for those tests/i/.

11-5

I The intended test sequence is contained in Table I. The purpose of the present report is to indicate expected values for the thermohydraulic quantities and parameter studies regarding the influential factors. These values and diagrams make possible an immediate evaluation of the measured values and,an extrapola-tion to other operating magnitudes.

The measurement of the magnitudes of interest is described. The measuring points of thermohydraulic importance are plotted in Figures 1.1 to 1.5. The strain measurement points essential for determination of the forces are indicated for quick evaluation of the load-stress variations.

The deformations of the structure due to the applied loads are not a sub)ect of this report. Additional measurement points are available during the hot tests to study this'complex problem.

2. 0 enin time and flow rate of the safet /relief valve Opening time and steam flow rate of the valves are not only of importance for the stressing of the relief system and suppression chamber, but also have considerable relevance from the standpoint of safety. Accordingly, these values deserve special attention.

Measurements of the opening time are already available, especially for the KhV valves built according to the same principles but designed for lower flow rates /8,9/. Zn addition, there are measurements in the GKM test stand for low syste=.-press res.

From these, an expected value of ca. /~%ms is derived for the KKB valve. In the load data of Sections 3 and 4, the opening ti.-,.e is varied from g~~~~gms in order to point out its influence and make interpolations possible when there are deviations from the expected value.

In order to be able to judge the overall opening behavior of the valves, the "not closed" and "open" contact signals at the pilot valve and the pressure variation in the control line are measured in addition to the lift vs. time variation at the main valve.

r Figures 2.1 and 2.2 show the valve flow rate expected bv the valve manufacturer as a function of reactor pressure. This flow rate can be measured through the flow limiter installed in the main-steam line at the outlet of the reactor vessel (see Figure 2.3) . Figures 2.4, 2.5 and 2.6 show the calculated characteristic 11-7

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curves of the flow limiter used to evaluate the measurements.

For comparison, the expected flow-rate variations for, blowdowns from one and two valves are plotted in these characte istic curves (Figure 2,5 and Figure 2.6).

11"8

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3. Internal ressure in the'blowdown ie and encher After the valve opens, steam flows into the blowdown pipe filled with air to the water level and causes a pressure rise which leads to expulsion of the water slug. As this happens there is a transient pressure-maximum (the so-called vent clearing pressure) which subsequently changes into the steady-state pressure.

3.1 Ex ected- vent clearinc ressures For the relief system with perforated-pipe quencher, a theoretical vent clearing model was developed which represents an extension of the corresponding model for the plain-ended pipe and was adapted to the GEM tests /5/. The expected values of the vent clearing pressure calculated with this model are shcsn in Figure 3.1 as a function of the reactor pressure and valve opening time. The loss factor in the nozzle was fixed at~+ 'gas an upper estimate, However, Figure 3.2 makes clear how slight the influence of this factor is on the vent clearing pressure.

In Figure 3.1, the maximum vent clearing pressure of gQ bar results for a reactor pressure of /+bar and a valve opening time of

~Q ms. The specificati'on is based on this value'.

Figure 3.3 shows the influence of an initial overpressure of 0.2 bar in the blowdown pipe. A clear reduction of the vent

,clearing pressure results from the lowering of the water level in the blowdown pipe caused by this overpressure.

11-9

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3.2 Ex ected stead -state ressures From the GKN meeasurements we can infer th e s tea d-y-state pressures at the quencher to be expected in th e p 1 ant. In Figure 3.4, the pressure to be ex p ecteed for the KKB quencher is plotted as a function of the reactor pressure r for the valve flow rate indi-cated by the manufacturer. 'or comparison we also note the

~

pressure rise that would result with a,~~ red uction of the quencher outlet area. The specification value for the max'-..um steady-state internal pressure is g3 bar.

Figure 3.5 combines the representatio o f F'igure 3.4 into a curve in which the stead-eady-state pressure is plotted as a func"io."

of the mass flow density relative to the total outlet area.

The effect of friction in the blowdown pipe is slight. For high flow rates, the p ressurre expected after the orifice plate which is inserted aft after the valve is only ca. gg bar higher than just before the quencher inlet.

3.3 Measurement of the ressure.

The pressures in the blowdown. pipe are measured blowd just after the orifice plate etimes also before that plate and just before somet the quencher inlet ~Fiigure u 1.3) . Fast pressure transducers are used I

and the he measurement me values are recorded transiently.

11-10

4. Vertical im ulse force durin water ex ulsion 4.1 Ex ected values of the vertical im ulse The water accelerated after opening the valve in the blowdown pipe is deflected in the quencher from vertical to horizontal motion. Consequently, there is exerted on the nozzle a downward d irected vertical force, equal in magnitude to the water's impulse, which is passed on from the blowdown pipe to the fixed point of the system. The non-steady motion of the water can be calculated with the vent clearing model described previously. The instan-taneous impulse of the water can then be derived from it. The vertical force increases as the water accelerates and vanishes as soon as all the water has passed the spherical central body of the quencher.

Figure 4.1 shows the calculated maximum vertical force as a function of the reactor pressure and valve opening time. As in Section 3, the loss, factor in the quencher was set equal to g~g Figure 4.2 shows clearly that this value has a distinct influence on the vertical force (as opposed to its effect on the clearing pressure). The expected loss factor is between I~Wand @~3, Figure 4.3 shows the effect of an initial overpressure of g~

bar in the blowdown pipe, which causes a distinct reduction of the vertical force.

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4.2 Measurement of the vertical im ulse The vertical impulse is measured in two different ways.

4 ~ 2.1 Strain measurement on the blowdown ie Figure 1.3 shows the positions of the strain gauges DS 1,2 arranged on the pipe in the longitudinal direction. These strain gauges detect the strains resulting from internal pressure, from temperature due to a heating of the inner wall and from the vertical impulse to be measured.

Figure 4.4 shows the longitudinal stress on the pipe due to an internal overpressure.

Since the temperature stresses on the outside of the pipe due to a temperature jump inside the pipe are practically proportional to that temperature jump, the representation can be limited to a normalized temperature jump of q~3'K. Figure 4.5 shows the temperature rise in the pipe, normalized in this way, for vent clearing times of 4~~~~and Q~ ms, it being assumed that the actual temperature corresponds to the saturated-steam temperature of the steam according to the occurring steam pressure. Figure 4.6 shows the time dependence of the stresses on the pipe's outer axis resulting from these temperature variations, according to the stress calculation described in /10/. The temperature variation from Figure 4.5 was approximated here by a staircase function with a step size of gQ ms.

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Finally, Figure 4 .7 shows the stress as a function of the vertical force to be measured.

4 '.2 Strain measurement on the restrainin structure A second measurement of the vertical impulse results from the strain gauges DS 24,25 (Figure 1.3) on the restraining structure.

Figure 4.8 shows the stress on the vertical supports as a function of the vertical force to be measured.

11-13

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5. Transverse force and torsional moment on 'the encher durin o eration In this Section we consider only those forces which arise from the operation of the quencher itself. Added to this are forces that occur when the adjacent quencher is in operation. These are discussed in Section 7. The total force results froa the sum of these components.

5.1 Ex ected values of the transverse force on a uenche" arm The forces on the entire quencher measured in the GP! test, stand were transposed in /5.11.12/ to the conditions present in the plant. For the specifications, the determination of the maximum transverse force on a quencher arm was based on the most unfavorable

-measurement value for the entire quencher. In dividing the force among the individual arms of the quencher, it was assumed that'he total force is generated by only Q arms. The division was done in such a manner that the most unfavorable transverse forces resulted for the individual arms.

This specification value for the transverse force is to be com-pared here with an expected value. Instead of the maximum value, we start out from a mean measured value smaller by a factor of Ik~ Furthermore, it is assumed that only~+ of tbe force is generated bye arms. The remaining quarter results from the other two arms. In this way, the mean expected value corresponds to half the specification value". The following Table makes this clear.

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Type of operation Expected mean Specified transverse force transverse force on a quencher arm on a quencher arm (static equivalent (static equivalent load) load)

Clearing after opening, the valve See Fig. 5.1 See Fig. 5.1 Closing the valve KRAFTWERK UNION Intermittent AG PROPRIETARY INFORMATION condensation The force application point lies in the middle of the quencher's hole array (lever arm to quencher center point: WMQm)-

5.2 Measurement of transverse force and torsional moment The transverse forces are determined by strain gauges on ~

arms of a quencher. The arms are each provided with two opposing strain gauges (DS 13/19 and DS 20/21) at a sufficient distance from .the welds to the central ball (so that neither notch stresses in the weld seam nor strain impediments due to the ball have an effect) (Figure 1.4). In the transverse force measure-ment, associated strain-gauges are connected in a "difference" configuration so that symmetric loads are cancelled out in first approximation and only bending stresses are indicated.

U Figure 5.2 shows the stress at the position of the strain gauge as a function of the transverse force.

Since the transverse force is measured on only /~/quencher arms, the total transverse force and the total torsional moment must be deduced from the resultants that are determined. A pessimistic F

11-15

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(estimate of the) transverse force on the entire quencher is obtained by g+++Qthe maximum resultants measured ove. the

~Q instrumented arms. In so doing, I

it was already taken into consideration that a force can also be exerted on the central body by the flow processes. Still to be added then is the force from the Ch~t arrays from iQ arm bottoms /18/, which is to be determined by calculation, and, unde." certain circumstances, a transverse force in the circumferential direction when the adjacent quencher is actuated, which is determined separa=e'y (Section 7).

Likewise, we get a pessimistic torsional moment for the entire quencher by 1+++/ the maximum resulting moment measured with their% instrumented arms. It should also be noted that a simultaneous occurrence of the maximum values of total trans-verse force and total moment can be ruled out. Rather, it is to be expected that one of the two quantities becomes small when the other reaches its maximum.

The transverse force represents only a small part of the load on the quencher arm. The symmetrical loads on the quencher, illustrated in Figures 5.3 and 5.4, are larger. Figure 5.3 shows the stresses due to internal pressure, whose expected value is given in Section 3, and Figure 5.4 shows the stresses on the outer fiber due to a temperature jump of +~~K inside the arm /13/.

The stresses are practically linearly dependent on the temperature jump. The maximum I expected temperature jump is~+'K ~

11-16

The highest stresses occur in the weld seam between quencher arm and central ball. Figures'.5 to 5.7 show the stresses on 'the quencher arm due to internal pressure, temperature jump and transverse force, as determined in /13/. In addition, we must still allow for a stress concentration factor in the veld seam, vhich according to /13/ is expected to be /~X Furthermore, it should also be noted that the quencher loads and their effect can also be judged by the displacement trans-ducer V D3 and the strain gauges DS 7, 8, 22, 23 provided on the bottom mount.

11-17

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6. Pressure at the bottom and walls of the su ression chambe" 6.1 Ex ected values durin vent clearin The air-water oscillations arising after the expulsion of air cause pressure amplitudes which have their maximum value near the quencher and decrease with increasing distance from the quencher. Vhile the maximum value depends on the boundary condi-tions fo" the vent clearing process, a function independent of the maximum value is expected for the pressure decrease with distance.

Therefore, it is appropriate to consider the peak value and the distribution separately. Zn a third subsection, statements are made concerning the superposition during the clearing of several quenchers.

6.1.1 Maximum ressure am litude near the encher The pressure amplitudes arising near the quencher after the clearing were investigated closely in the GKM test stand. The l

measurement results and the transposition of these magnitudes to the plant are illustrated in detail in /5/. Additional studies are contained in /6/. Tbe transposition of the measured values from the test stand to the plant starts from the assumption that the oscillation process remains the same as long as the combinations of parameters that stimulate and influence the process remain constant. Table 2 makes it clear that both the parameter com-bination characterizing tbe expulsion of air (row 6) and also the parameters influencing the spreadiqg of the ai (rows 7 and 8)

are transposed practically as constants. Therefore, the measurement results obtained in the test stand also represent the -expected values for the hot tests.

According to model tank tests /6/, the pressure amplitudes at the bottom are onlv slightly dependent on the clearing pressure (in contrast to the plain-ended pipe) (Fig. 6.1) ~

QMMMMMM~MMMMMMM LM~~~MMMMMMMMMMt KRAFTWERK UNION AG PROPRIETARY INFORMATION With this dependence, the following pressure amplitudes relative to a unit clearing pressure of QQ bar can easily be converted to other clearing pressures corresponding to the expected values listed in Section 3 ~

Figure 6,2 shows expected upper values for the pressure amplitude as a function of water temperature. Typical values toce he" w'he associated parameters are:

Clearing pressure Water temperature Max. p"essure a.-."'=-".

bar oc ba" 11-19

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These amplitudes correspond to the highest values measured in the test stand. The considerable 'scat'ter band'ue to the differing amounts of damping during air expulsion also encompasses values up to ~+ lower.

The rise of the pressure amplitudes with water temperature occurs because, corresponding to the state of saturation, the steam remains in the air bubble to an increasing degree, which then acts like an additional quantity of air and reinforces the air oscillations.

With an initial overpressure o~~lbar in the blowdown pipe, the pressure amplitudes are increased by ~~ bar due to the additional quantity of air. A typical upper expected value is:

Overpressure in Clearing Water Hax. pressure the pipe pressure temperature amplitude bar where the associated parameters have been recorded again. It should be pointed out that for an initial lowering of the water level in the blowdown pipe, clearing pressures different from those in the normal case are applicable (see Section'3).

6.1.2 Pressure distribution in the circumferential direction and in the vertical center section Whereas in the preceding Section we discussed only the max'-..'=

11-20

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pressure amplitudes expected in the umnediate vicinity of the quencher, we shall indicate here the decrease of this pressure with distance. It was shown in detail in /4/ how the air-water oscillation treated theoretically in /14/ can be applied to the conditions of the quencher. The fact that the laws derived for an infinitely large water volume are also valid, in principle, for the pool of the suppression chamber bounded by walls, could be demonstrated by the evaluation of 19lM tests contained in /15/.

According to that, the laws are almost fully app'icable in the circumferential direction of the suppression chamber, but also I

in the vertical center section with a few restrictions.

Figure 6.3 shows the expected distribution of pressure amplitudes in the circumferential direction of the suppression chamber.

The pressure distribution based on the stress analysis is illus-trated for comparison in Figure 6.4.

The expected distribution in the vertical center section is plotted in Figure 6.5.

6.1.3 Superposition during the clearing of tm guenchers Throughout the entire operative range of the relief system, only clearly separated valves (never two adjacent valves) are actuated simultaneously in the plant. Furthermore, even for simultaneous actuation it, is not to be expected that the clearing and the a'r oscillations proceed fully coherently at two quenchers. In order to investigate the superposition of, the processes at two quenche=s, 11-21

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two immediately adjacent quenchers and also two widely separated quenchers are actuated simultaneously during the tests. The expected values illustrated in the following are based on the assumption that the processes proceed coherently and therefore represent an upper estimate.

Figure 6.6 shows the expected superposed pressure distribution for two closely adjacent quenchers. Unit distributions were assumed for the unperturbed individual distributions of the quenchers. The mutual raising of the maximum pressure amplitude (caused by a mutual. interaction during the air expulsion phase, which is conceivable during the formation of the air oscilla ion, i.e., before the occurrence of the maximum amplitude) is con-sidered to be g~. The increase results from the following reasoning: The maximum pressure amplitude during the air expul-sion phase is less than~g of the later maximum value. At the position of the adjacent quencher,Q~ of this is effective for the assumed undisturbed distribution {see Figure 6,6). But this is less than~i of the maximum value. The maximum value is increased by this percentage Figure 6.6 shows further that no appreciable pressure drop from th'e maximum value occurs between the'wo quenchers, since the mutual interaction coincides in first approximation with the reaction of a wall between the two quenchers (reflection), wh'ch hinders a decrease of the pressure amplitude.

11-22

Zt is hardly conceivable that a quencher could have an appreciab'e effect beyond an adjacent vent bking cleared simultaneously (except for the raising of the exit'ressure level at the adjacent quencher itself). Thus, the pressure decrease there is expected to follow the same (normalized) curve as tha of the unperturbed individual distribution.

Figure 6,7 again shows the superposed'distribution for closely adjacent quenchers - here in a representation normalized to l.

Figure 6.8 compares the specified distribution with the press'e distribution expected for 2 simultaneously actuated quenchers separated from each other by 100'. The distribution curves agree with those of the unperturbed process at one quencher {see Fig re 6 3) ~ Ho appreciable influence of one quencher on the pressure amplitude of the other is to be anticipated, since the undisturbed pressure amplitude of the individual quencher has already decayed at this distance. Between the two quenchers it is expected that the higher value of the two individual distributions results.

6.2 Ex ected values durin condensation Thorough investigations of the oscillations occurring during condensation, based on GKM measurements, are presented in /4/.

Translator's note: German word here could mean either "exi."

or "initial".

11-23

According to them, stochastic pressure oscillations (noise) having an amplitude of F~Q~ ~a.

are expected in the pool during condensation with supercr't'ca pressure ratio. According to the model measurements, pear.

amp 1 i tud e s o f bar are not exceeded even in the vicinity of the quenchers.

During condensation with subcritical pressure ratio, pressure oscillations of uniform frequency and amplitude with ap <p~ bar, n >

rp/~

can arise due to synchronization of the oscillation processes at the individual steam bubbles from the approximately g~~out et openings of a quencher. These condensation oscillations are expected to decay according to the same distribution curves as for the air oscillations (Section 6.1) .

During condensation with very small mass flows, the condensation process can become unstable. Then water enters and exits rhythmically at the quencher. Associated with this are inter-mittently excited pressure oscillations whose maximum total excursion, according to model measurements, does not exceec those of the uniform pressure oscillations.

6.3 Measurement of the ressure distribution I

The positions of the transducers used to measure the maximum 11"24

I pressures in the suppression chamber and the pressure distri" bution are sho~~ in Figures 1.1 and 1.2. An angular range of 100's covered in the circumferential direction. The pressure distribution in the vertical center section is measured primarily at 135'position of quencher A). The pressures are recorded by fast transducers on strain-gauge base via carrier-frequency measuring amplifier.

11-25

7. Forces on internal fittin s due to relief rocesses The pressure oscillations during the clearing of a quencher cause forces not only on this quencher itself (Section 5) but also on the other internal fittings in the suppression chamber. In particular, we may mention here:

- .an adjacent quencher,

- adjacent vent pipes or protective tubes,

- struts and

- ribs.

The loads on these components are described in more detail in

/16,17/. The specification value applicable for the pressure difference in the circumferential direction over a protective tube down to a submergence of+3m is KMM~MMMM~%

These loads are measured by foil strain gauges. The measurement for the quencher has already been described in Section 5. To facilitate, the evaluation, stress-load diagrams are given in Figures 7.1 to 7,3 for a protective tube (strain gauges 33/34 and 35/36), a strut (strain gauges 26/27) and the measuring rib (strain gauges 39-44).

11-26

The temperature in th e bl o wdown pipe is measured between the valve and the downstream orifice plate, besides on a pipe also ca.Q~Wm above the water level * (Figure 1.3) . It is expected that the temperature should correspond to the th saturated-steam temperature of steam, both during th e p ressure build-up phase prior to the clearing an d a 1 so during steady-state condensation.

In the annular i gap between blowdown p p e and p rotective tube, the temperature is measured on a pipee both in the water region and also in the air region (Figure 1.3). The measurement values obtained here enable us to obtain information concerning the heating of the water and a possible evaporation on durin g shutdown in the longer-lasting tests. Estimates may ma be found in the Appendix of /16/.

The operation o f th e quencher que throughout the operative range of the relief system can be c h ec ked with the temperature measurement points in the hole array of the quencher (Figure ure 1.4 (the conden-sation should occur in the joint flow meth od ~~ with draw-off of water from the pool through the water path of the quencher) .

According to model measurement inn the GEM test stand and in the

. model tank, a temperature lying below the bo'boilin temperature slator 's note: The apparen arent ambiguity in this sentence mirrors

~. ro.

a similar ambiguity in the o ig whether 2 or 3 different measurements are e ng es Inspection of the cited Figure 1.3 should clari y i

~*Tr. note: Literal trans 1 a tion o of German "Hitstromverfahren".

11-27

I prevails in the water paths as far as the middle 'ddle of the hole array throughout the entire operative rang of the quencher.

Extensive temperature measurements in the p ool are being made in the vicinity of quencher B (Figures 1..1 and 1.2) . It is expected that the deviations are no more tha In addition, it should be noted that the responding temperature measurement points are equ ippe d with w sheathed thermocouples having a diameter of 1.5 to 3.5 mm.

11~28

I Table 1: Vent clearing and condensation tests Status 1 Tabelle 1 s Freiblase- July 1974 und Nondensationsversuche Stand: 1 ~ 7 ~ )974 tSEE NEXT PAGE FOR KEY)

Vers. Reaktor- Abblase- gentil- asser llehgruppe Demerkungen Nro druck dauer Nr. esp.

I (bar) 3 min 35 10 s 10 o irxrZriZ1~

10 o 10 s 10 s A i B D 1 10 s Q

~

8<11171117/i 10 s 10 s 10 10 s LLLLLLL%

10 s 12 5 s A i C D 2 13 5 ~ A B D 1 (LLLLL3 Abbl assn~

bis auf 70 bar Q/3 ca.45 o 15 ca. 125 s N LLW 16 ca ~ 3 loin %L%

17 ca ~ 4,5 min i%%%

18 eel 4~5 min B Wo 1e. 2 ein C vir~o N ILL~

2 sin su geschalte 19 co 10 can 8 A)i 19a ca. ,3 .win A vjrMf ~

3 coin su-gcschalte 20 B

~Il 20a ca. ,4 min C 4

vir&f sin su-geochal to o

Ãr, 11-29

KEY FOR TABLE 1

1. Test no.

2. Reactor pressure

3. Blowdown duration

4. Valve no.

5. Water temperature

6. Measurement group

7. Remarks

8. Possibly 80 9, Blowdown to 70 bar

10. C is connected for 2 minutes

11. A is connected for 3 minutes

12. C is connected for 4 minutes 14 LMM%B

15. Increasing to

16. K~~MM%h~~~~~~~M~&i

17. Double test

18. Holding pauses due to RPV 11-30

KRAFTNERK UNION AG PROPRIETARY INFORMATION 11-31

relief valve tests g~

KKB pre sure an~tmperature measurement p nts " St Status 9/20/74 9/2

.F I stand 2U.9.'i4 Oruck-und Temperaturme(lste((en Bitd Fiaur l.l lXY: l.

2.

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17/18 Pressure measurement points i QruckmeOslellen

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~Cco Meridian 105'fauOer TO) for T13) %D

E KRAFTWERK UNION AG PROPRIETARY INFOKCATION 11-34 ~:ure

I

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R k

400 I

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KKEI - Kennfetd des Durchflu0begrenzers Figure 2.4 KKB - Characteristics of the ffov limiter

l I

l

according to valve Flow 'rate of two valves manufacturer's informat i O Durchsatz zweier Ventile ncIch Angaben des O Durchsatz einesvalveVentils Flow rate of one Ventil herstellers 400 300 Ol d

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4, ~

200 O7bo'o 100 10 20 40 50 60 70 80 eaktordruck ( bar )

eactor pressure Bild 2.5: ',hi" 5 KKB - Kennfetd des DurchftUObegrenzers Figure 2.5 KKB - Characteristics of the flow limiter 11-38

I l

Flow rate of two'alves according to valve O Durchsotz zweier Ventile manufacturer ' information noch Angaben des Flow rate of one valve Yentilher stellers O Durchsotz eines Ventils

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KKB - Kennfetd des DurchftuBbegrenzers t

Figure 2. 6 KKB - Characteristics of the flow limiter 11-39

-KRAFTWERK UNION AG PROPRIETARY INFOK4ATION Figure....... 3.1 6.6 11-4 0 11-58

REEEEJKES

/1/ Weisshaupl Wurgassen nuclear power plant. Expected pressure loads during vent clearing tests at KWW for various pressure levels.

AEG/E 3 - 2370, October 1972

/2/ Weissh'aupl, Rupp KWW - Relief valve tests 'in November 1972 Interpretation of measurement results - Valve behavior and reduction of initial shock AEG/E 3 - 2442, November 1972

/3/ Slegers, Molitor, Hof fmann Outlet geometries for the pressure relief pipe in the BWR; First development results AEG/E 3 - 2465, January 1973

/4/ Becker, Frenkel, Melchior, Slegers Construction and design of the relief system with perforated-

)

Pipe quencher KWU/E 3 - 2703, July 1973

/5/ Becker, Hoffmann, Knapp, Kraemer, Melchior, Meyer, Schnabel Vent clearing with the perforated-pipe quencher KWU/E 3 - 2848, October 1973

/6/ Werner Experimental investigations of vent clearing in the model test stan" KWU/R 521 - 3129

/7/ Rupp KKB - Specification for the vent clearing tests in the non.-

nuclear hot test KWU/V 822, July 1974 11-59

/8/ Weisshaapl-KWW - Opening behavior of the pressure relief valves AEG/E 3 - 2336, 3nd Addendum, August 1972

/9/ Hofmann Determination of dead times and opening times of a KWW safety/

relief valve in the DFVLR, Porz-Wahn AEG/E 3 - 2361, September 1972

/10/ Kampel MRB calculation R 1.8205

/11/ Knapp, Hoffmann Design load for blowdown pipe and perforated-pipe quencher Spec."No. KKB/XK/SD 001, Rev. 1, December 1973

/12/ Survey description of the load on all components of the relief system Letter tothe IRS of 5/17/74

/13/ Hampel MRB calculation R 1.8203 b

/14/ Weisshaupl, Koch Formation and oscillation of a sphercial gas bubble under water AEG/E 3 - 2241, Hay 1972 11-60

l

~

~

~

~

/15/ Frenkel, Becker, Nowotny, Schnabel KKB pressure distribution in the suppression chamber during clearing of the relief pipe, taking into consideration'the KWW tests in November 1972 AEG/E 3 - 2486, January 1973

/16/ Becker Design specification, pressure and temperature load for the protective tube of the relief system Spec. No. KKB/XK/SD 003, Rev. 0, March 1974

/17/ Becker et al.

Design specification Load on the bracing of the pipe submerged in the pool of the suppression chamber Spec. No. KKB/XK/SD 010

/18/ Knapp, Hoffmann Design load for the bottom mount, of the perforated-pipe I

quencher Spec. No. KKB/XK/SD 002, Rev. 1, Dec. 73 11-61

I