ML17138A547
| ML17138A547 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 08/02/1977 |
| From: | Hoffman, Schmid PENNSYLVANIA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML17138A531 | List: |
| References | |
| R521-41-77, NUDOCS 7903150373 | |
| Download: ML17138A547 (22) | |
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PROPRIETARY INFORMATION 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 INFORMATION')
Use of blocked out areas by cross hatch bands in the report text and figures/tables, e.g.
i) ...." with a mass flow density ofQM~1Kg/m2s...";
MMM"mm iii) should be kept below NWZc4 atm."
iv) 8/17/78
AEG-TELEFUNKEN NUCLEAR REACTORS Ffm., August ',72 E3/E2-SA Dr..B/Schn/ru Re ort No. 2327 AIR OSCILLATIONS DURING. VENT CLEARING WITH SINGLE AND DOUBLE PIPES COMPANY CONFIDENTIAL Prepared: /s/ Schnabel, E3/E2-SA
/s/ Becker , E3/E2-SA Checked: /s/ Frenkel, E3/E2-SA Classified: /s/ Grabener, E3/El Class II
Distribution list:
E 3 - Secretariat E 3/V E 3/V 1 E 3/V 2 E 3/V 3 E 3/V 4 E 3/V 5 E 3/V 4-KWW E 3/E E 3/E 1 E 3/E 2 E 3/E 3 2 x E 3/E 1 LP E 3/E 2 E 3/E 2 / SA 4 x E 3/R
,E 3/R., 1 E 3/R 2 E 3/R 3 E 3/R 4 E 3/R 5 E 3/R 2-KL E 3/Library HE/E-F
NONLIABILITYCLAUSE This report is based on the latest state of the art in science and technology achievable by our best possible efforts. The knowledge and experience of AEG-TELEFUNKEN- are incorporated in it.
However, AEG-TELEFUNKEN and all parties 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.
This reservation does not apply insofar as the report is delivered in fulfillment of contractual obligations, nor with respect to licensing authorities or the experts appointed by them.
AEG-TELEFUNKEN reserves all rights to the technical information contained in this report, particularly the right to apply for patents.
Further dissemination o'f this report and of the information contained therein requires the written approval of AEG-TELEFUNKEN.
Moreover, this report is communicated under the assumption that it will be handled confidentially.
Table of Contents Pacae
- 1. S ummary,
- 2. Statement of problem
- 3. Test set-up 7 -
- 4. Compilation and interpretation of the GKM test results 8 4.1 Dependence of the pressure peaks on /he pressure build-up in the vent pipe (vent cleaiing pressure) 8 4.2 Dependence of the pressure peaks on the valve opening time 4.3 Pressure profile at the bottom for the single and double pipes Re ferences 12 Tables 13 Figures 14
- l. ~Summar A total of 29 'tests to investigate the air oscillations after vent clearing were performed in the AEG condensation test stand in the Mannheim Central Power Station (GKM). The tests were carried out with a single NW 150 or NW 200 pipe and with ag, NW 150 double pipe. The vent pipe submergence and the valve opening time were intentionally varied.
Zt was found that the pressure peaks beneath the central pipe are at most equal to the pressure in the vent pipe at the time of the vent clearing. When plotted against the valve opening time, the measurement points representing the pressure peaks fall along a uniform curve. No significant influence of the submergence or, pipe geometry is revealed.
The tests show further that the assumption of an additive
.superposition of the central pressure peaks, as was made in the Loading Specification for the KWW suppression chamber bottom, is conservative.
- 2. Statement of the roblem When a relief valve is blown down, the water slug located in the pipe has to be expelled during the flow initiat3.on process.
A cushion of compressed air is formed between the water slug and the steam flowing behind it. When this air cushion emerges from the pipe, it begins to expand rapidly. Physical models I
that provide good agreement with experimental results have been described previously in /1/ and /2/. In this report, test results shall be used to investigate the quantities that have a substantial influence on the pressure peaks of the gas bubble oscillation. In addition, the pressure profile at the bottom'f the tank during simultaneous blowdown through a double pipe having a pipe separation of 600 mm is compared with the profile for a single pipe.
The vent clearing tests were performed in the GKM test stand illustrated in Figure 3.l. This test stand i's used for vent clearing and condensation tests. A detailed description of the test stand is contained in /3/.
The test stand is connected to the steam system of the GKM via
/
an NW 200 pipeline. Superheated steam at 20 kg/cm (gauge) and ca. 280'C can be obtained from that system.
An NW 200 repair gate-valve, which is mounted directly on the steam header, represents the beginning of the experimental section and simultaneously delimits the test stand from the GKM.
An actual KWW rel'ief valve is located approximately 25 m down-stream from this repair gate-valve. After opening the relief valve, steam is conducted into the following vent pipe and condenses in the water pool of the test tank.
Some of the tests described here were performed with the test set-up using a double pipe, as illustrated in Figure 3.2. In the vicinity of the distribution point from the single pipe to the double pipe, the off-center pipe could be sealed off from the rest of the test stand by means of a pipe blanking disk. ~
The most important dimensions and instruments are shown in Figures 3.1 and 3.2.
- 4. Com ilation and inter retation of the GKM test results Vent clearing tests were performed in GKM on a vent pipe with mass flow densities such as those that occur when a relief valve is blown down. The measurements were made on a single pipe (NW 200 or NW 15) and on a 2 x NW 150 double pipe. Besides the vent pipe submergence, the valve opening time was also varied in the tests. All tests performed to investigate the vent clearing process in GKM are compiled in Table 4.1 togther with,the parameters of greatest importance for the vent, clearing process.
4.1 Dependence of the pressure peaks on the pressure build-up in the vent pipe )vent clearing pressure)
N During the vent clearing process, there is a pressure build-up in'the vent pipe. It causes an acceleration of the water column standing in the pipe, but simultaneously also causes a compression of the air column. At the instant of expulsion of the water column (either the water slug is expelled in its entirety or the following air bores a channel in the water pool), the air column is under maximum compression. Therefore, it may be expected that the maximum overpressures during the subsequent air oscillations do not exceed this vent clearing pressure.
The investigations relating to this question are summarized in Fig. 4.1. In that Figure, the measured pressure peaks beneath the pipe (beneath the central pipe in the double-pipe configura-tion) in the second oscillation are plotted versus the vent clearing pressure. The second oscillation was used for the evaluation because it is in the second oscillation that the
larger overpressures occur, even compared to'he first oscillation.
The first expansion of the air bubble probably already begins before the entire volume of air has left the vent pipe.
Accordingly, energy continues to be fed in during the'irst'scillation, so that the second pressure peak can be higher'igure 4.1 shows that the measured pressure peaks at~the bottom were found to be at most equal to the vent clearing pressure.
The condensation shocks, which are superimposed on these pressure peaks and falsify the result, were not taken into consideration here. However, most of the measurement points were found below the vent clearing pressure, which can be explained by the fact that a damping had already occurred in the second oscillation.
Finally, it should be noted that no significant differences were found with respect to the nominal bore, submergence and number of pipes.
4.2 Dependence of the pressure peaks on the valve opening time In the preceding Section, a relation was found between the pressures measured at the bottom beneath the pipe during the air oscillations and the pressure in the vent pipe at the t
instant of vent clearing (vent clearing pressure). However, the vent clearing pressure is not a very suitable magnitude for practical applications. In searching for a more suitable physical magnitude, the following analysis is relevant: The pressure build-up in the vent pipe is surely depen'dent on the time variation of the valve opening process. It is therefore
obvious to investigate the dependence of the pressure peaks on the, valve opening time.
The last tests, in which the displacement-vs.-time function of the valve piston was measured directly, revealed the followi'ng problem concerning the valve opening time: In slow opening processes, the valve lift does not increase linearly with time.~ Instead, there can be a slower increase at the beginning and at the .end of the opening process, as is illustrated in a graph in Figure 4
4.2. In the earlier tests, some of which were discussed in /3/,
the valve opening time was determined by another method. There, a valve opening time was extrapolated linearly by using 2 contacts which were separated from the upper and lower end points (Figure 4.2). The start and gradual end 'of the valve lift process are disregarded in that method. The switching point of the contacts is not very exact and thus represents an additional uncertainty.
Therefore, the valve opening time was determined from the pressure before the orifice which precedes the valve. The dependence of the pressure peak beneath the pipe during the same oscillation on the valve opening time determined in that way is illustrated in Figure 4.3. The measurement points yield a uniform variation which is approximated by a curve drawn through them. For short opening times, high pressure peaks are produced, but they decrease very quickly as the valve opening time is increased and tend toward a low limiting value for very slow valve opening processes. No significant influence of. the submergence, the 10
pipe nominal bore or a superposition due to the second pipe ca' be found from Figure 4.3.
4.3 Pressure profile at the bottom for the single and double pipes Figure 4.4 shows a comparison of the pressure profiles at the bottom for a single pipe and a double pipe. Both tests were performed with a submergence of .Pa~m and approximately> identical valve opening t'imes. Approximately the same pressure peaks were found centrally,.as shown in Figure 4.4.
In regard to the superposition of loads caused by 2 pipes blowing down simultaneously, a statement was already made with Figure 4.3.
Both for the NW 200 and NW 150 single pipes and for the NW 150 double pipe, the pressure peak beneath the central pipe was found to depend only on the valve opening time. Hence, no superposition of the pressure peaks occurs. However, the Load Specification for the KWW suppression chamber bottom, described in detail in /4/, is based on an additive superposition. Thus, the tests performed in the GKM with single and double pipes V
demonstrate that that Load Specification is =conservative.
REFERENCES
/1/ Weisshaupl, Schall Calculation model to clarify the pressure oscillations in the suppression chamber after the vent clearing AEG E3 2208, March 1972
/2/ Slegers, Weisshaupl, Becker, Zieglowski, Kleinow, Schall KWW - D'esign load for the suppression chamber bottom AEG - E3 2238, May 1972
/3/ Berndt, Proyer, Becker, Schall, Vaida, Frenkel Condensation tests in the GKM with single pipe AEG E3 >> 2301, August 1972
/4/ Nowotny, Slegers, Andersen KWW Specification Loads for the suppression chamber bottom KAl XA - SD 001, July 1972 l
12
KRAFTNERK UNION AG PROPRIETARY INFORMATION 13
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KEY FOR FIGURE 3.1
- 1. Water injection
- 2. Throttle valve
- 3. Repair gate-valve
- 6. Signal line, NW 25, 20 kg/cm (gauge)
- 7. Drain
- 8. Safety valve
- 9. Tests 1-25
- 10. Steam admission ll. Air addition
- 12. Vent
- 13. air
- 14. Water ="admixture
- 15. Snifter valve
- 16. Capability, for air connection
- 17. Pressure gauge
- 18. Damage:
p4 failed in Test 4 p5 failed in Test 5 p4 I 5 I 6 I 7 failed in Test 8
- 19. Inside diameter 207 mm
- 20. Cross-over pipe
- 21. Lance
- 22. 2 struts at 5.5 m and 3.58 [?] m
- 23. p> is rearranged at 255 mm below zero beginning with Test No. 7, with separate supply pipe beginning with Test No. 10 15
KRAFTWERK UNION AG PROPRIETARY INFOMCATION Valve lift max 1st reed contact i2nd reed contact valve opening time from time reed contact measuremen actual valve opening time Diagram of the valve opening process
KRAFTWERK UNION AG PROPRIETARY INFOMIATION 4.3 Figure......'.
18
KRAFTWERK UNION AG PROPRIETARY INFOMCATION Flgure1 4,4
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