ML20030E060
| ML20030E060 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/15/1981 |
| From: | Litton F Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20030E021 | List: |
| References | |
| NUDOCS 8109170367 | |
| Download: ML20030E060 (5) | |
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9/15/81 UNITED STATES OF AMERICA NUCLEAR REGULATORY CONMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
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PENNSYLVANIA POWER AND LIGHT C0.
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Docket No. 50-387 ALLEGHENY ELECTRIC COOPERATIVE, INC.
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50-388
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(Susquehanna Sten. Electric Station.
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Units 1 and 2)
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NRC STAFF TESTIMONY OF FELIX B. LITTON REGARDING STRESS CORROSION CUCKING IN BWR STAINLESS STEEL PIPING (Contention 7b)
Q.1. Please state your came and position witn the NRC.
A.1 My name is Felix 3. Litton and I am a Senior Materials Engineer in the Materials Engineering Branch, Division of Engineering, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Comission.
Q.2. Have you prepared a statement of professional qualifications?
A.2 Yes. A copy is 'ttached to this testimony.
Q.3. Please state the scope of your responsibilities for the review of the operating license application for the Susquehanna facility.
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- A.3 I am responsible for the review and evaluation of those sections of the Applicants' Final Safety Analysis Report for which the Matarials Application Section of the Materials Engineering Branch has primary review responsibility. This responsibility includes a review of the materials used for the construction of the reactor coolant pressure boundary and methods for inspection to preserve camponent integrity.
Q.4 What is the purpose of your testimony?
A.4 The purpose of my testimony is to address Contention 7b which states:
The Nuclear Stean Supply Systems of Susquehanna 1 and 2 contain numerous generic design deficiencies, some of which may never be resolvable, and which, when reviewed together, render a picture of an unsafe nuclear installation which may never be safe enough to ope rate. Speci fically:
The cracking of stainless steel oiping in BWR coolant water environments due to stress corrt3 ion has yet to be prevented or avoided.
Q.5 What causes stress corrosion cracking of stainless steel piping in BWR coolant water environments?
A.5 Leaks and cracks in the heat-affected zone (HAZ) of welds that join austenitic stainless steel piping and associated cumponents in boiling water reactors (BWR) have been observed over the past several years.
Pip.e Crack Study Groups were formed both by the Nuclear Regulatory Commission and the General Electric Company to study and evaluate the problem. Both Study Groups reached equivalent conclusions. They concluded that three main conditions l
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3-must be present for intergranular stress corrosion cracking (IGSCC) to occur. The conditions are: (1) tensile-type stress, including residual stress from fabrication, (2) corrodent, an environnent in which electrochemical reaction can occur, and (3) material susceptible to intergranular stress corrosion. The degree to which one of these conditions must be present for intergranular corrosion to occur is variable and depends on the degree to which the other conditions 're present.
Q.6 Has the NRC Staff established guidance for reducing the susceptibility to cracking of BWR stainless steel piping?
A.6 Yes. NUREG-0313, Revision 1, ' Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping," dated July,1980, sets forth methods acceptable to the NRC Staff for reducing the susceptibility to intergranular stress corrosion cracking of ASME Code Class 1, 2, and 3 boiling water reactor pressure boundary piping and safe ends.
Q.7 Have the Applicants followed the guidance set forth in NUREG-0313, Rev. 1.?
A.7 Yes. The Applicants have followed the guidance of NUREG-0313, Revision 1.
(See Supplement 2 to the SER at page 5-1). They have 4
undertaken an extensive program to reduce the potential for intergranular stress corrosion cracking in austenitic stainless s teel piping systems. Regular grade Type 304 stainless steel has
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. been replaced with low carbon grade Type 304 stainless steel in the Recirculation System Discharge Valve Bypass Line, Core Spray and Head Sprayer System, Reactor Water Cleanup System and Instrument Piping and Bottom Drain Lines.
In those lines where the regular grade of Type '304 stainless steel has not been replaced, the au;cented inservice inspection guidance of NUREG-0313, Revision 1, will be performed.
Q.8 Will the Applicants' program assure that stress corrosion cracking at the Susquehanna facility will not endanger the health and safety of the public?
A.8 Yes, the Applicants program is based on an accurate and full understanding of the cause of intergranular stress corrosion cracking in SWR stainless steel piping systems.
Its implementation will minimize each contributing factor to the cause of intergranular stress corros !an cracking. Furthennore, if intergranular stress corrosion cracking does occur, the augmented inservice inspection to be perfonned by the Applicants will assure that cracks are detected before leakage occurs.
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PROFESSIONAL QUALIFICATIONS FELIX B. LITION I am a Senior Materials Engineer in the Paterials Engineering Branch of the Office of Nuclear Reactor Regulation, Nuclear Regulatory Commission.
I am attached to the Materials Integrity Section and am responsible for the review and evaluation of materials and processes used in the construction and operation of compon,ents -in the nuclear power industry.
Py education consists of a B. S. (1936) and M. S. (1937) degree in t
Physical Chemistry from Virginia Polytechnic Institute, Blacksburg, Va.
I have completed adaitional study in Material Science (1967) at the University of New Mexico and have taken special courses in Fracture Mechanics (1977) at' George Washington University.
Prior to joining the Nuclear Regulatory Commission, my experience consists of metallurgical research related to the preparation, fabrication and alloy forration of new structural materials for nuclear, advanced aircraft and high temperature application.
I have published in technical journals on the environmental behavior, thermodynamic stability and i
mechanical properties of uranium, plutonium, vanadium, zirconium, titanium, hafnium and silicon and their alloys. My experience in ferrous metallurgy relates to the cause of failure in service.
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