ML20236E518
| ML20236E518 | |
| Person / Time | |
|---|---|
| Issue date: | 02/19/1985 |
| From: | Vollmer R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Roller W DETROIT EDISON CO. |
| Shared Package | |
| ML20236E258 | List: |
| References | |
| FOIA-87-666 NUDOCS 8710290257 | |
| Download: ML20236E518 (15) | |
Text
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1 FEB I ? 1985 Mr. William R. Roller Plant Superintendent Monroe Power Plant Production Organization P. O. Box 731 Monroe, MI 48161
Dear Mr. Roller:
.I want to thank you for the time and courtesy you and your staff extended-to us during our visit to the Monroe Power Plant.
Knowledge of incidents such as the steLm line break at Monroe is important to our mission and we appreciate j
the opportunity to see the physical situation and discuss it with you. As additional information which could be released by Detroit Edison becomes avail-able, I would like to be kept informed.
During our visit several photographs of the ruptured pipe were shown to us which displayed the open fish mouth crack and.the general shape of the pipe after the failure. We would appreciate getting copies of them for our report to the Commission. The identification numbers are C-695-86-H-15, C-695-86-H-3 and C-695-86-H-19.
Sincerely.
Original Signed By:
Richard H. Vollmer Richard'H. Vollmer, Deputy Director Office of Inspection and Enforcement Distribution:
RH Vollmer L,54u A65/
JM Taylor A %da 865 D IE 11mer
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8710290257 871029 PDR FOIA SEPEB7-666 PDR
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PIPING. ISSUES IN NUCLEAR SYSTEMS IN'THE U.S.A.
.A. Taboada, L. C. Shao l
USNRC, Washington, D. C. 20555, U.S.A' I
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R..H. Vollmer
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TENERA Master Limited Partnership Bethesda, Maryland, U.S.A.
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ABSTRACT 1
Issues dealing with major problems of. piping for nuclear reactor systems.are discussed. Plans for implementation of the USNRC Piping Review Committee reconnendations on resolving
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the intergranular stress corrosion cracking problem in boiling _
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water reactors are detailed including alternative acceptable mitigative actions and guidelines' for. crack evaluation and repairs.- The problem of pipe wall thinning due tu erosion /
I corrosion, highlighted by a major pipe break in the Surry Power Station, is described.
1.
Introduction The USNRC has been addressing.a series of piping problems in- -
nuclear systems since, as early as, 1965 when cracking was
. reported in the Dresden I nuclear plant. More,recently, the NRC-Piping Review C$sunittee (PRC) wEs formed to perfom a:
comprehensive review of these actions and of the overall requirements being applied to safety related~ nuclear piping..
_ As part of tNs review the co$fttee comp 1 ted an in depth
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LevaluationofthEfollowing'sub3scO: stressjirrosion^
l crackinginpipingofboilingwaterreactors(BWR), seismic design, potential for pipe breaks and other dynamic loads and load combinations.
- Formerly with the U.S. NRC.
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implementing report also upgrades the monitoring of coolant leakage and leakage limits.
~ A number of materials have been identified as resistant to
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IGSCC. These include austenitic stainless steels which have been solution heat treated after welding and austenitic stainless steels containing low carbon levels such as_ Types 304L, 316L, 304NG, 316NG and, 347. Also identified as resistant to IGSCC are weld metal and cast metal with low carbon and at least 7.5% ferrite content and pipe weldments when the weld heat affected zone are protected by'a cladding of corrosion resistant weld metal.
Other alternatives that provide protection from 16 SCC apply special or controlled processing during or after fabrication.
These include (1) solution heat treatment to remove sensiti-zation,- (2) heat sink welding in which the major portion' of the weld is made with cooling water inside the pipe to mini-mize sensitization caused by welding and to induce compressive stresses on the inside surface at the weld and, (3) several stress improvement processes that result in compressive stresses on the inside surface. The stress improvement pro-
. cesses considered fully qualified to provide resistance to IGSCC include the induction stress improvement process and the mechanical stress improvement process.
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a Control'of water chemistry is considered to be an important way to reduce IGSCC in sensitized materials. The report recommends that hydrogen water chemistry (HWC) be implemented and that impurities such as sulfates', chlorides and carbonates bbpt_ to a ve'ry low 1hel.' However, since the response of _
BWRs to hydrogen injection differs from plant to plant generic specifications are yet complete er.d the individual HWC programs would be reviewed by the Mc on a case basis.
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3.' Pipe Wall Thinning Due to Erosion / Corrosion On December 9,1986, an 18 inch pipe fitting in the non-nuclear part of the Surry Power Station ruptured cata-trophically causing serious damage and injuries which resulted in fatalities to personnel.
This event highlighted to the NRC and the U.S. Nuclear Industry the problem of wall thinning of carbon steel piping containing a single phase fluid caused by the com-bined effec'ts of erosion-corrosion.
Prior to this incidence of pipe wall thinning in the U.S. nuclear plants had generally been limited to certain parts of secondary systems with two phase flow. The Surry failure energized the industry to reevaluate the situation.
The Surry Power Station is a two unit plant with three loop PWRs each rated at 775 MWe. The plant started operation in
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1972 and had accumulated 76000 hours of operation when the failure occurred in the suction line to the main feedwater The failure occurred as a complete separation of an pump.
18-inch pipe at an elbow attached to a 24-inch feedwater condensate supply header which was operating at 370'F with a flow rate of 17 ft/sec. The reaction forces of the pipe break resulted in severe distortion and buckling of the pipe and the complete separation of a large fragment that was propelled approximately 20 feet. ' All injuries were
- caused by the release of high pressure steam.
A metallurgical failure analysis of the failed pipe per-fomed by Brookhaven 18aiiional Laboratory [3] revealed that
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the failed elbow had been globally thinned on the inside surface and had a scalloped appearance, typical of erosion-corrosion. The elbow material had been reduced in some areas to below 0.040 inch (1.02 mm) from the installed 5
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Unexpectedly, wall thinning was also found in straight sections of-the main feedwater piping system to the extent that the minimum allowable wall thickness would have been violated by the next outage. This finding was apparently the first case of wall thinning found in safety related piping inside of containment.
Further, the region of thinning was at least eight feet from an elbow that would i
cause flow turbulence. Further evaluations indicate that these regions were found inadvertently and were not selected for inspection by the criteria-recently developed by EPRI for l
detonnining the most likely locations for erosion-corrosion.
i It was reported that high flow velocities of 22 ft/sec existed at these locations and that these in combination with other operating factors may have caused the thinning.
At this time the specific piping with wall thinning at the Trojan Nuclear Plant has been replaced. The NRC has issued an E43 alerting other utilities to the problem, infonnation notice and has' established a' task force to further evaluate the impli-cations of this event.
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References (1) NUREG-1061., Volumes 1-5, Report of the U.S. Nuclear Regulatory Commission Piping Review Committee April 1985.
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(2) NUREG-0313. Rev. 2. Technical Report on Materials Selection and Processing Guidelines for 8WR Coolant Pressure Boundary Piping (Draft Report) June 1986.
(3)- NUREG/CR-458 ~ Metallurgical EvNuadon of an 18-!
Feedwater Line Failure at the Surry Unit 2 Power Station.
March 1987.
(4) NRC Infonnation Notice No. 87-36:
Significant Unexpected Erosion of Feedwater Lines. August 4,1987.
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TRIP. REPORT TO M0HAVE' PLANT Background.
4 General information to public
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Severity of injuries Fossil plant Reason for visit - Impact on nuclear plants Description.of incident Failure
. Pipe break in. reheat system - Explosion? -
Location - Next to change house i
Steam release - Killed and injured people i
Description of plant i
Fossil.. steam plant Built in'1973 i
Operating conditions Pressure & Temperature (Design and Operating) 4 Description of Pipe and System l
Size 30" D 2" thick Standards: - ASTM A 155, A 387 Plate Materials'- Welded Pipe - 1 1/4 Cr Mo O-Inspection - Radiography of Weld Operating conditions - 10000F 600 PSI.
l Manufacturing process - Subarc welded Design Criteria l
Description of failure j
t length - 15.Ft Locetion - Axial weldment (weld and Har)
Fracture appearance Pipe. appearance Evidence of flaws 'or deterioration corrosion, creep, fatigue, etc.
Plant Operating History Years of operation l
other failures Maintenance and inspection experience S.C.E. Actions to date L
Inspections Failure analysis Board inspectors actions to date Additional inspection requirements r ture actions planned R
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'ossible causes of fail U
Implication to nuclear Mustry Sumary L _
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Detroit Edison /EEI Presentation on Monroe Power Plant Hot' Reheat Line Failure Cartier Roosa - Detroit Westin Hotel October 29, 1986
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FINAL AGENDA l
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Introduction & Welcome i.
Harry' Tauber, Group Vice President-Detroit Edison
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8:20.- 9:00 Monroe Power Plant and Failure Event
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_W. R. Roller, Superintendent-Monroe Power Plant 9:00-10:30':
Metallurgical Examination and Failure Analysis y J. E. Schaefer, Metq:1urgical Research Engineerz Detroit Edison' j l
- g. - D. J. Connell,- Senior Engineer-Detroit Edison 10:30-11:00 Qventions & coffee Break
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-11:00-11:45
- Nondestructive Examinations I
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g J. R. Mullens, Nondestructive Examination
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Engineer-Detroit Edison-l J. E. Schaefer, Metallurgical Reseyrch Engineer-Detroit Edison A
11:45-12:00 Questions i
12:00-1:00 Lunch.- Riverfront Ballroom 1:00-1:45 Engineering and Welding h J. H.'Casiglia, Piping Equipeant Engineer-Detroit y
Edison J. D. Black, Welding.Evginser-Detroit Edison 1:45-2:30 DetroitEdisonSteamPipingInhpectionProgram D.'W. Baker, Supervising Engineer: Boilers 6.
- *M Auxiliaries-Detroit Edison s-2:30-2:45 Break 2:45-3:45 EPRI Status Report on Seam Welded Piping
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B. Dooley, Manager-Life Extension - EPRI fR.Viswanathan,TechnicalAdvisorensterials Support-EPRI L. Becker, Special Projects Manager-F,PRI NDE Center 3:45-4:00 WRAP-UP r
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. Monroe' Power' Plant and Failure Event n
a.
Introduction'to Monroe Power Plant b.-' Rupture sad Injury Summary.
Condition of Plant - Asbestos and Damage c.
d.. Plant / Engineering Mobilization a.
Metallurgical Examination and' Failure Analysis a.
Material Specification b.
Macroscopic c.
Microscopic-d.
Life Fraction Calculation Leak versus Rupture Analyses
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Crack Growth Studies g.; Failure Analysis Nondestructive Examinations Overview of Techniques Utilized a.
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- b. -Preliminary Investigation - Failed Section
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- c.. Preparation and Inspection of Remaining Piping - MT&UT d.
.NDE of Welding Repairs j
e.
Replication i
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Correlation of MT/UT, Replication and Metallurgical Examinations Engineering and Welding
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'Initia1' Design Review and Evaluation a.
b.
' Detailed Stress and Code Compliance Evaluations f
c.
Hangers and Supports d.
Welding requirements and Procedures Detroit Edison Steam Piping Inspection Program
- a.. Development of program
- b.. Monroe Power Plant - Inspection of other units c.
Other Detroit Edison Plants
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d.
Cost and Schedule
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/ia LINE/ FAIL.
TOURS THURSDAV, OCTOBER 30, 1986 Board bus at the river side entrance to the hotel-street level (between Kyoto and Dionysos restaurants).
Busses will return to the Westin at approximately 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br />.
MONROE POWER PLANT Board the bus marked "EEI/ Detroit Edison-Monroe Plant" by 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br />. Tour will include an overview of Monroe Plant and the steam line inspection l
underway.
The group will be accompanied by W. R. Roller, Superintendent and G. R. Edgerton, Operations Engineer, Monroe Plant.
DETROIT EDIS0N ENGI_NEERING RESEARCH
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Board the bus marked "EEI/ Detroit Edison-Engineering Research byJ830 hours.
Tour will include a walking tour of the laboratory facility and discussion and viewing of weldments from the failed pipe.
The group will be accompanied by J. C. Guillaumin, Engineering Research.
1 5 MAC00NAC LEVEL E,,
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C MACKINAC BALLROOM elevetors, or take the
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e GAME ROOM eDOMED SWIMMING POOL eEXPRESS ELEVATOR TO THE SUMMIT The World of Shops is located WORLD OF SHOPS EdM on the first and second levels h
of Town im inroogh an e ACCESS FROM STREET LEVEL Take either the World of Shops escalators (located between l
Towers 100 and 200 and Towers
$1 NM g,'L 300 and 400) or the speral C
ek staircases inside the atrium ek space from Level 1(Stnset Level) to reach the second levet of the World of Shops.
To find your way around,look 1 STREET LEVEL N
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3 THE SUMMIT, ARE escalators are located on the j
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LOCATED ON THE o_
walkways leading to the j
PROMENADE LEVEL g
guestroom elevators.
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l EAESCALATORS a ftL1 PHONES O RESTROOMS
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17 QUESTION AND RESPONSE FORM I
Ny name is
' Utility t
My question / comment is. directed to:
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- t-l Speaker Please check one:
Question C Commenti j
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l Speaker's' Answer:
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Please return this form to the registrattore desk following the current session.
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1 I-QUESTION AND RESPONSE' FORM I
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i My question / comment is directed to:
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Please check one:
Question C Coninent M i
Speaker's Answer:
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Please return this form to the registration desk following the current
- session,
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