ML20023D266
| ML20023D266 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 05/11/1983 |
| From: | Nothelfer T, Plummer M COMMONWEALTH EDISON CO., NUTECH ENGINEERS, INC. |
| To: | |
| Shared Package | |
| ML17194B556 | List: |
| References | |
| COM058.0011.000, COM058.0011.0007, COM58.0011.000, COM58.0011.0007, NUDOCS 8305200307 | |
| Download: ML20023D266 (18) | |
Text
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. Project File No. COM058.00ll.0007 Test Specification No. COM-58-003, Rev. O Test Plan & Procedure No. COM-58-005, Rev. 0 I PRELIMINARY TEST REPORT ON DYNAMIC TESTING OF DRESDEN 2 MECHANICAL PIPE SNUBBERS I
Prepared for:
Commonwealth Edison Company Prepared by:
NUTECH Testing Corporation 6830 Via del Oro San Jose, California 95119 I
Jrepared by ,
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Date: May ii , t %3 l Toriy NothelW 4 Test Engineer NUTECH Testing Corporation l Reviewed and Approved by Date: Nt .[T3 M. C. PlVmmer, Ph.D.
Executive Director NUTECH Testing Corporation 8305200307 830513 PDR ADOCK 05000237 S PDR
. CoMoss. coll. coo 7 !
Page 2 of 17 ;
1 INTRODUCTION I
A series of dynamic tests were performed on three mechanical pipe snubbers manufactured by Pacific Scientific, Model PSA-10.
The objective of the test program was to determine whether I
or not snubber damage, recently observed at Dresden 2, was caused by an excessively high dynamic loading or the consequence of a non-standard installation. The non-standard installation
! incurs a noment across the snubber in addition to the dynamic loading. The tests were performed from April 18 to April 30, 1983 at NUTECH Testing Corporation using three PSA snubbers.
This preliminary test report is intended to provide a " Quick Look" summary of the key test results. The Final Test Report will contain a more comprehensive description of the test conditions and observations. Although the results provided herein are considered final, they should be used for information only since they are undergoing final Quality Assurance review.
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. COM058.00ll.0007 Page 3 of 17 TEST HARDWARE The three Model PSA-10 snubbers which were dynamically tested at NUTECH Testing Corporation are listed below. These three snubbers were provided by Commonwealth Edison Company to NUTECH Testing Corporation.
Manufacturer Pacific Scientific Anaheim, CA 94803 Model No.: PSA-10 Mechanical Snubber Serial No.: 13999, 13994, 14012 The following connecting hardware was used.
Forward Bracket for Model PSA-10 No. 1801597-03 I Manufacturer: Pacific Scientific Rear Bracket for Model PSA-10 No. 1801558-07 Manufacturer: Pacific Scientific l
A schematic of the NUTECH Testing Corporation snubber test facility is shown schematically in Figure 1. The method of i
applying a moment across the snubber is shown in Figure 2.
The moment applied across the snubber is equal to 36 inches (L) times the applied force (F). A sketch of the test apparatus to measure the snubber deflection due to an applied moment is provided in Figure 3.
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COM058.0011.0007 Page 4 of 17 TEST PROGRAM Pre-Test The snubbers were pre-tested to check their operability prior to applying the large dynamic loads. All three units could be moved back and forth manually. The breakaway force was measured for each snubber. At the beginning of each dynamic test, the snubber was installed in the test facility (attached to hydraulic actuator) tnd the lockup acceleration checked.
All three units received from Commonwealth Edison Company met these initial pre-test checks (requirements).
I Test Series No. 1: Transient Dynamic Load I This single pulse load test series was deleted since it was considered redundant with Test Series No. 2.
l E Test Series No. 2: Repeated Dynamic Load I In this test series the snubbers were subjected to the repeated transient dynamic load (shocks) as shown in Figure 4. A peak dynamic load of 10 kips was initially applied. The snubber was then checked for failure (e.g., manual travel check, break-away force, dynamic loading). The test was then repeated, I
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Page 5 of 17 increasing the peak dynamic load in increments of 5,000 up to 28,500 lbs. Note, the entire test series was performed I without a moment.
I Test Series No. 3: Dynamic Load with a Moment .
In these tests the snubbers were tested with a moment applied across the snubber, which simulates the non-standard instal-l l I lation. The snubber was subjected to the same series of tests as described in Test Series No. 2; however, with a moment across the snubber. Initially, the moment was set at 500 ft-lbs (6,000 in-lbs). Later tests in the series were performed with higher moments (up to 4,300 ft-lbs).
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COM058.00ll.0007 Page 6 of 17 I RESULTS The snu'ber o operated successfully when subjected to a peak dynamic load as defined in Test Series No. 2, of up to 28,500 lbs. The snubber maintained all of its pre-test performance capabilities (i.e., manual check, breakaway force, lockup acceleration) after this dynamic load testing.
An applied moment of 500 ft-lbs across the snubber resulted in a .050 inch relative lateral displacement across its length.
This snebber, with the applied moment, was tested at various levels of the 10 cycle dynamic load (Test Series No. 2) up to 29,300 lbs. It remained fully operable throughout the test. The snubber subsequently passed all of the post-test chec:cs (manual, breakaway, lockup).
1 A snubber was finally damaged when a 3,000 ft-lb moment was applied. This moment resulted in a 0.2 inch lateral displace-
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ment across the snubber. The peak dynamic load applied was l 9,900 lbs during the 10 cycle event which damaged the snubber.
Metal filings were found below the snubber and the snubber could not be manually stroked. A second snubber was also tested to failure by applying a maximum moment of 4,300 ft-lb lI which yielded a .23 inch displacement. This snubber was tested at various dynamic loads up to 18,900 lbs with 10 cycles per event.
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. Page 7 of 17 The two snubbers tested to failure were disassembled and exam-ined. Metal shavings averaging about one-half inch in length and one-quarter inch in width were found inside the support cylinder. Small metal filings were also found inside the l
support cylinder. The telescoping cylinder was badly gouged.
A brief list of dynamic tests performed and highlights are provided in Table 1. Typical test data from these tests are provided in Figures 5 to 8.
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. COM058.00ll.0007 Page 8 of 17 CONCLUSIONS The PSA-10 mechanical pipe snubber sustained, without degrada-tion of performance, several dynamic impulse load events up to at least 29,500 lbs with 10 cycles per event. In addition, l the unit sustained these dynamic events with a simultaneous E 500 ft-lb moment.
I On the other hand, the PSA-10 mechanical snubber was damaged when a moment of 3,000 ft-lb was applied across the snubber, causing a lateral deflection of 0.2 inch. The damage observed in the test was similar to that noted at Dresden 2. Note, the t
peak dynamic load applied in conjunction with the 3,000 f t-lb moment was 9,900 lbs.
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M M M M M M M M M M TABLE 1 . .
MECHANICAL PIPE SNUBBER (PSA-10) DYNAMIC TEST PROGleM Applied End Snubber Serial Number Test Peak Dynamic Morient Deflection and Test Run No. Series Load, lbs. ft-lbs. in. Test Results SN 14012 Fully operable a er Run #2-6 #2 28,500 0 0 testing - no dan sge SN 13994 Fully operable after Run #3-6 #3 29,300 500 0.05 testing - no damage SN 13994 #3A.1 9,900 3,000 0.20 Snubber failed
- Run #3A.1-2 Damaged internally **
SN 13999 '
Run #3A.2-14 #3A.2 14,300 4,300 0.23 Snubber failed
- Damaged internally **
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- Snubber could not be moved n;anually, breakaway forco was at least 10 times normal, lockup acceleration near pre-test.
- After the test, the snubber was disassembled and inspected. The following damage was noted: The support cylinder had gouged the telescoping cylinder leaving behind metal shavings or filings.
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