ML20088A623
| ML20088A623 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point, Perry, Catawba, Byron, Braidwood, Surry, North Anna, Clinton, Midland, 05000000, Marble Hill |
| Issue date: | 03/28/1984 |
| From: | Jim Dodson PACIFIC AIR PRODUCTS CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-84 NUDOCS 8404120307 | |
| Download: ML20088A623 (15) | |
Text
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3133 West Harvard Street. Santo Ana, California 92704 PO. Box 5277. Telephone 714/557-1710. Telex No. 67-8319 I
fla rch 28, 1984 United States Nuclear Regulatory Commission 1717 H Street, N.W.
Washington, D.C.
20555 Attention:
Director, Office of Inspection & Enforcement Regarding:
Final Report and Conclusions -
Pacific Air Products Co. Linear Converters Investigation Gentlemen:
Pacific Air Products Co. has been investigating the causes of abnormal wear on linear converter units that we have manufactured and furnished to power generating facilities, both nuclear and conventional.
We began this investigation in January of this year, after becoming aware of the abnormal wear of units at the Edae-water Generating Plant (coal).
Shortly thereaf ter, some units at the Byron Nuclear Station also exhibited similar wear patterns and were returned to our facility for exam-ination.
Considering that we have furnished almost eight hundred of the linear converter units to power plants throughout the Country, it was the decision of our top management to handle
.the situation as a potentially reportable item under the 10CFR Part 21 regulations.
We filed notification with the Nuclear Regulatory Commission and conducted the investigation to determine if a generic defect did exist in the linear con-verter unit.
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(2) i The investigation and test program have been completed with the following conclusions:
1.
Linear converter shaft guides and bearings require lubrication for the standard brass components.
2.
Linear converter units that show abnormal wear have been cycled many more times than original design had considered to be the life span of the unit.
3.
Related components of the HVAC system may be being cycled so much during start-up testing that they are, in effect, worn out and should be replaced.
Based on the results obtained during testing, Pacific Air Products Co. has taken the following steps:
1.
Notified all customers of test results and co ncl u s i o ns.
2.
Provided all customers with field lubrication procedure to be employed on linear converters.
3.
Provided all customers with maintenance inter-val information and alternate lubrication options available.
4.
Notified all customers of actuator / system
" hunting" condition that could affect their piant.
We have concluded that a generic defect does not exist in the linear converter unit.
As built and installed at present, with brass shaft guides and bearings, the units will pe rfo rm the designed function for the normal life span of the unit.
Lubrication will extend the interval between maintenance.
The field lubrication procedure that was developed is included as part of the attached correspondence.
All test data, records, photographs and materials are available for review at our Santa Ana, California facility.
If you have any questions, please contact me at (714) 557-1710.
Sincerely, PAC'FIC A PRODUCTS C0.
C HCJk 0 U%
ames P. Dodson Director of Quality Assurance Attachments:
7043-38, Report 7043-03 (Part III), 7043-P1 Clifford Hale, U RC. Reaion V. Arlinaton. Texas cc:
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. 3133 West Horvord Street. Santo Ana, California 92704. P.O. Box 5277 Telephone 714/557-1710. Telex No. 67-8319 March 26,1984 Log No. 7043-38
'.. (To Utilities, Engineers, etc.
on attached list.)
Attention:
Quality Assurance Director Regarding:
(Project)
Investigation Findings Linear Converter ( Abnormal Wear)
Gentlemen:
On February 1, 1984, we issued a concern under 10CFR21 regarding the. linear converter we manufacture, to the effect that we had some cases of abnormal wear reported.
0n March 7, 1984, we issued a report of the second por-tion of our investigation into the problem.
Since.the issuance of the first-and second reports, we have been involved in an extensive testing program as well as
-field investigation.
' Attached to this letter is our Investigative Report No. 7043-03 (Part III) which out-lines the causes of the abnormal wear pattern and the measures that are needed to prevent the re-occurance of the problem.
To over simplify the investigation and its results, the explanation is:
"The cause of the abnormal wear is and was actuator
' hunting' (for whatever reason) and the solution is lub-rication."
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Even though-this1 statement is "brief", i t is based upon thousands of test hours on various lubricants, guides,
~ bearings and materials, all of which culminated in the final round-the-clock tests conducted af ter selection of lubricant.
1.
A linear -converter with' a 40 foot pound torque load,. lubricated in accordance With our field maintenance procedure, ran more than 1,000,000 34" cycles or 2,000,000 3h" strokes.
This'is 50 times the require-ments set 1forth -in IEEE 382-80 for modula-ting actuators and 500 times the IEEE 382-80
~
requirement for two position' actuators.
During the course of the test, the linear converter was relubricated at approximately 330,000 cycles and at 660,000 cycles.
2.
A test running simultaneously with the above test was a linear converter equipped with lubricant impregnated shaft guides and bear-ings, as described in our Investigative Report No. 7043-03 (Part III) under the title " Main-tenance/ Rebuilding Program No.
3",
which also ran 1,000,000 3h" cycles WITHOUT LUBRICATION OR MAINTENANCE.
If the linear converters are put on a regularly scheduled
. maintenance program and are lubricated before and during service in accordance with the Linear Converter Lubrication Procedure (attached), the linear converters can absorb the
- system-abnormalities without abnormal wear to the linear converters..
~
Should you desire to convert your linear converters to the "no maintenance" version or.if you desire our services at any time, please feel free to call.
If you have difficulty in obtaining the recommended lubricants, we have a ready
- supply in stock.
Unless we disc'over any unusual conditions, abnormalities or field conditions that would af fect your linear converters, thist letter an.dithe-attachments conclude our investigation and our concerns and we feel that our responsibility under
' 10CFR21 has been fulfilledi
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A copy of1the complete test data logs, photos, field reports, etc., is on file in our office in Santa Ana, California.
We will be glad to ' arrange _ an appointment for you.to' review ~ this test report in detail at our office should you desire to-dn so.
Thank you for your patience and understanding.
If I can be of service,~ please call.
Very truly yours, PACIFIC AIR-PRODUCTS C0.
Louis R. Hess President LRH:dg Attachments:
' Investigative Report No. 7043-03 (Part III)
Field Lubrication Procedure No. 7043-P1 cc:
S u b.iec t :
LLinrear Converters PAPCo.'s final report (7043-03-Pa'rt I I'I ) da ted 3/22/84 and PAPCo Field Lubrication Procedure 7043-P1 was sent to the C
following with PAPCo transmittal letter dated 3/26/84.
I cc:
Sargent &_ Lundy (Q.A.)
v'ILLIN0IS POWER COMPANY l/
Steve Ornber (S&L)
Clinton Power Station Rick Servey Ill i no i s Pow '
Cl nt n inois cc:
Sabol & Rice BINGHAM MECHANICAL P.O. Box 1856 1300 Pancheri Drive-Idaho, Falls, ID 83401 Willkomm Co., Inc.
cc:
WISCONSIN POWER & LIGHT CO.
Sargent & Lundy (Q.A.)
Columbia Generatir.g Station Steve Ornberg (S&L)
Milwaukee, Wisconsin 53081 Willkomm Co., Inc.
cc:
WISCONSIN POWER & LIGHT C0.
Sargent & Lundy (Q.A.)
Edgewater Generating Station S. Ornberg (S&L)
Sheboygan, Wisconsin 53081 Joe Dalheimer ( Aldag)
Bechtel Ann Arbor (Q. A. )
VkONSUMERSPOWERCOMPANY cc:
Midland Nuclear Power Station Midland, Michigan 48640 MCC Powers-Skokie (Q.A.)
VThe CLEVELAND ELECTRIC ILLUM. CO.
cc:
c/o Perry Nuclear Power Plant P.O. Box 97 Perry, Ohio 44081 cc:
Bahnson Service Co. (Q.A.
v# DUKE POWER COMPANY Catawba Nuclear Station Newport, S.C.
29730
'cc:
Stone & Webster (Boston) p' VIRGINIA ELECTRIC & POWER C0.
P.O. Box 26666 Richmond, Virginia 23261 Stone & Webster (J. Plant-
/
cc:
V NIAGARA M0 HAWK POWER CORP.
West 300 Erie Blvd.
Syracuse, N.Y.
13202 1/'PUBLIC SERVICE CO. INDIANA cc:
Sargent & Lundy (Q.A.)
S. Ornberg (S&L)
Marble Hill Generating Station P.O.
Box 190 New Washington, Indiana 47162
l/.,1:iM0llWEALTil EID50tl COMPAtlY
- c
Sargent & Lundy ( Q. /. )
c/o Braidwood Sta tion S. Ornberg (S&L)
P.O.
Box 81
'Bracevill, Illinois 60407
- \\/ COMM0flWEALTH EDISON CO.
-c/o Byron Station cc:
S. Ornberg (S&L P.O.
Box B Sargent & Lundy (Q.A.)
Byron, Il l i no i s = 61010 Shankar Planjery (S&L)
Jim Westermeyer (Comm Ed.
14., k >
L United NRC 1717 H. Street NW Washington,-D.C. 20555 JCliff Hale
.U.S.
NRC Dallas, Texas J
A,
INVESTIGATIVE REPORT NO. 7043-03 (Part III)
DATE:
March 22, 1984
SUBJECT:
Investigation Findings Pacific Air Products Co. Linear Converter INVESTIGATION CONDUCTED BY:
L.R. Hess, President James P. Dodson, Director of Quality Assurance William Nagurski, Engineering Project Manager CAUSE:
Recent on-site inspections have confirmed our suspicion that the abnormal. wear on the linear converters was caused by abnorr?'
actuator oscillation, normally called " hunting".
We have con-firmed that the following conditions exist when abnormal wear
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conditions have been reported:
1.
The ITT actuator does hunt when it is at the end of the power stroke (when the spring is compressed).
The hunting varies in frequency depending on the condition of the high pressure hydraulic seals.
From the ones we observed, the frequency of oscillation ranges from one every three minutes to four every minute.
This condition is unique to the electro-hydraulic actuator.
The actuator stem moves a dis-tance of from 3/16 inches to 3/8 inches.
Since the linear converter is linked directly to the actuator stem, this oscillation causes the linear converter
. input shaft to move the same distance.
i At ~an oscillation frequency rate of one every three minutes, the number of short strokes of wear on the linear converter would be:
Per Hour 20 Per Day 480 Per Month 14,400
'Per Year 172,800
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2.
An additional cause of actuator oscillation (hunting) is caused by the location and type of sensing elements that control the actuator such as:
A.
The location of-volume sensing devices that are directly influenced by velocity stratifi.-
cation thus giving false velocity readings which are overcorrected by the sensing units and the open/close cycle is started.
(This process was explained in our Bulletin dated March 7, 1984.)
We estimate that the frequency of this type of oscillation ranges -in a cycle time of two to four per minute.
At an oscillation fre-quency of two per minute, the number of cycles on the linear converter would be:
Per Hour 120 Per Day 2,880 Per Month 86,400 Per Year 1,036,800
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This type of hunting is particularly bad be-cause.the length of the stroke can be as much as 3h" versus the 3/8" stroke as mentioned under Paragraph #1.
B.
The location and type of thermo sensing devices cause much the same oscillation pattern.
A particularly acute problem in thermo sensing devices is the setting of the differential con-trol.
There seems to be a tendency to set the differ-ential at the minimum which causes the sensing device to overreact.
.If this problem is present, it rarely shows up in the occupied space and is, therefore, rarely detected unless it is observed at the damper actuator.
When sensor differentials are set too fine (close) the actuator never arrives at a normal position; it is always seeking a posi-tion to satisfy the sensor, i
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We estimate the oscillation rate due to this condition to be as high as 10 short cycles per minute.
At this rate, the number of short strokes would be:
Per Hour 600 Per Day 14,400 Per Month 432,000 Per Year 5,184,000 3.
The third, and probably the least recognized cause of actuator oscillation is system unbalance.
This is particularly prevalent during the start-up phase of the construction program.
Whole systems are subjected to this unbalanced stage during start-up and remain so until the system is completely balanced.
There is no way to estimate the cycle frequency under these con-ditions, but it is substantial.
It-would appear that regardless of the cause, short and long stroke actuator oscillation _does exist and should be recognized as having far reaching effects such as:
f[)
1.
Abnormal wear on linear converters.
2.
A much shortened life expectancy for the electro-hydraulic actuators.
3.
A shortened life expectancy for the damper itself.
4.
Increased frequency of maintenance on all components.
5.
Possible actuator, linear converter, damper or entire system failure if the system con-ditions go undetected.
CORRECTIVE ACTION
-It is apparent that on-site / system abnormalties do exist and probably will continue to exist and therefore measures will haveito be taken to absorb these conditions into the linear con-verter design and maintenance program to minimize the effect of the Labnormal ties.
It is obvious that in some circumstances, the linear converters as furnished will fail unless certain prevention
(_])and maintenance procedures are followed.
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)LAtthe1first report of~ abnormal wear on a linear converter J
1(January 15, 1984), we immediately ' issued a " concern" under 10CFR21.' At.the same' time, we established an extensive investi-
'gation.and test program to diagnose the cause and cure.
In conjunction with the testing-program, we undertook a program of! conferences with concerned engineers and on-site personnel.
.-Thi s - combi ned4 with extensive on-site inspections, has given us
-the background to' recommend certain corrective action procedures to prevent abnormal linear converter wear due to system abnormal condi tions.
Our~ recommended items are as follows:
A.
Correct the abnormalities causing the actuator
'" hunting".
B.
To protect against the effects of actuator
" hunting"~, establish an effective maintenance program such as_ the one recommended-in our attached Maintenance Bulletin.
To prepare this Maintenance Bulletin, we have been testing for all-related phases such as:
1.
Various Llubricants and their ability to function 'under load for extended periods.
2.-
Various' lubricant impregnated sintered materials.
' CONCLUSION With theJcompletion of-the testing. program, the field inspection-program 'and the issuance of 'the ' corrective action to be taken, we have -fulfilled our obligation as ~a manufacturer of the linear
. converter.
All of the direct causes of the-abnormal wear character-istics noted:were beyond our control.and were.far beyond the only published data forJactuator qualification as published in IEEE382-80.
.Wer do, however, ; willingly accept the responsibility to work hand in hand with' the utilities and the engineers to expedite the cor-rective action measures as -fast asi can be efficiently done.
We recommend.that the user select any one of the three following programs
.that best suits their needs:
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A
\\ J-MAINTENANCE PROGRAM NO. 1 The first maintenance procedure involves lubrication as recommended in Maintenance Bulletin 7043-Pl.
This procedure provides for the
. lubrication on input shaf t guides, racks and gears and output shaf t bearings without the necessity of removing the linear converter or the actuator.
The actual lubrication process will take less than ten minutes. We feel confident that if this procedure is repeated every six months, the linear converter will operate at least 2,000 full cycles and 100,000 20% strokes.
MAINTENANCE PROGRAM NO. 2 The second maintenance procedure involves returning the linear con-verter to the factory for a more comprehensive application of special lubricants as recommended in Maint.enance Bulletin No. 7043-Pl.
This procedure requires that the linear converter be removed from the damper, totally disassembled, lubricated, reassembled and reinstalled.
Our tests indicate that if this maintenance procedure is repeated every 2h years, the linear converter will operate 2,000 full cycles or-100,000 20% cycles.
(3
%j MAINTENANCE / REBUILDING PROGRAM N0. 3 Our tests on linear converters equipped with lubricant impregnated bronze shaft guides and bearings and utilizing polished input and output shaf ts coupled with surface impregnation of molybdenum disul-fide will produce a linear converter capable of operating for six years (or 250,000 full cycles) without maintenance.
' Note:
Our recommendations all reference cycles as the time factor for repeated maintenance.
This, of course, is due to the fact that the number of cycles and the length of the stroke determine the wear and the time / effectiveness of the lubri-cant.
To convert the cycle factor to a time factor, a time / cycle study must be done - possibly for each damper.
Then the damper maintenance pro-gram should be monitored to' prove the effective-ness of the program.
(6)
A SERVICES:
PAPCo personnel are ready to provide assistance in the mainten-ance program you may select.
We have in stock the recommended lubricants, spare parts, replacement loaner linear converters, etc.
We also have available mobile service units and technicians to provide services on site should they be desired.
Please contact us for prices on parts and service.
7%
Louis R. Hess, President r8
. U.
'V es P. Dodson, Director of Quality Assurance
/k WilliamNagurski,Pdo c t Manager J
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O Field Lubrication Procedure No. 7043-P1 LINEAR CONVERTER MODEL SL100LC This procedure is intended to provide instruction for field personnel in the acceptable method of adding lubricants to the StiOOLC linear converter manu-factured by Pacific Air Products Co.
Field lubrication of the linear converter unit should be performed:
- 1. When the damper is installed. prior to start up of the syJam for testing.
- 2. During normal shut down period of the equipment or system.
- 3. After excessive cycling of the equipment or usage beyond actuo-for manufacturer's recommended period of maintenance.
The field lubrication procedure requires the following tools or materials:
. One %" box end wrench.
- 2. One large screwdriver,
- 3. One trigger type oil con with flexibb spo
- 4. One stiff bristle brush (acid brush or tooth brush).
- 6. Dow Corning Molykote G-n Poste or Exxon Unirex N 2 Grease.
O PLEASE NOTE: LOCK OUT ELECTRIC UNTil REQUIRED l
J."M 1.
2.
Rotate domper to fait position.
Remove and retain four bolts Linear converter input shaft and lock washers from linear i
should be fully extended.
converter end plate.
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4 Shde knear converter end
' s Apply a generous amount of 3
oil between the output shaft plate off input shaft.
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and bearing. An applicator g
with a flexible spout is best
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suited for this purpose.
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5.
6.
ADoly a generous amount of Apply a generous omount of grease between the gear and grease to the lower input shott rock to all exposed creas of ond both end plate shaft the gear and rock with a short guides.
bristled brush.
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8.
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Silde end plote onto input shaft Rotate damper 90* to actuo-
'b}/h'[Q/lll
.'"'s Jeg and replace four bolts and tor's full up position.
lockwoshers.(Finger fight only)
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b.
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9.
p 10.
Remove plastic cover plate g
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Apply a generous amount of
. from actuator.
grease to the upper input shott.
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4 11.
12.
Cycle unit from full open to full Replace ITT cover plate. Tighten close several times to evenly J.
four bolts on linear converter distribute lubriconts.
4 end plate.
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a PACIFIC AIR PRODUCTS CO.
P.O. Box 5277, Santa Ana CA 92704 Telex 678319 Phone 714/557-1710
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