ML20054A607
| ML20054A607 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 04/14/1982 |
| From: | Murphy E NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | |
| Shared Package | |
| ML20054A606 | List: |
| References | |
| NUDOCS 8204160004 | |
| Download: ML20054A607 (5) | |
Text
t t)
\\
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
)
)
WISCONSIN ELECTRIC POWER COMPANY
)
Docket Nos. 50-266 50-301 (Point Beach Nuclear Plant,
)
(Repair to Steam Generator Tubes)
Units 1 and 2)
)
i l
AFFIDAVIT OF EMMETT L. MURPHY Q.
State your name and position with the Nuclear Regulatory Commission.
A.
My name is Emmett L. Murphy.
I am a Materials Engineer in the Inservice Inspection Section, Materials Engineering Branch, Division of Engineering, Office of Nuclear Reactor Regulation, of the U.S. Nuclear Regulatory Commission.
Q.
State your professional qualifications.
l A.
A copy of my professional qualifications is attached to my testimony in this proceeding submitted on October 26, 1981.
Q.
What is your response to the Licensing Board's question #1 posed in its Memorandum and Order dated April 7,1982, which reads:
Are any of the 12 tubes sleeved as part of the authorized tube-sleeving demonstration project dented?
(What basis has been used to answer this question?)
f A.
Moderate denting has been reported at Point Beach Units 1 and 2.
Whether or not denting has occurred in the tubesheet for the sleeved tubes at Unit 1 has not been reported to the Staff.
If denting was 8204160004 820414 PDR ADOCK 05000266 G
t i present in these tubes it was not severe enough to interfere with the insertion of the sleeves.
Q.
What is your response to the Licensing Board's question #2 which reads:
'If any of the 12 tubes do suffer from denting, is there any substantial safety risk associated whii the presence of the degree of denting present?
(Please provide reasons for this conclusion.)
A.
Denting, if present in the sleeved tube assemblies, does not represent a safety concern.
NUREG-0886 states that sleeve repairs are not considered to be a viable repair alternative for tubes degraded by denting. What is meant by this statement is that when denting has become sufficiently advanced to necessitate tube repairs, we do not believe sleeving to offer a viable long term repair option for the affected tubes. The original inner diameter (I.D.) of the tubing is.775 inches. A reduction in tube diameter (denting) as a result of corrosion product buildup in the tube-to-tubesheet or support plate crevices increases the potential for stress corrosion cracking at the location of the dent.
It has been general industry practice to plug tubes which restrict passage of a.540 inch diameter eddy current probe during inservice inspection of the tubes. This criterion is based upon operating experience and is intended to prevent the occurrance of leaks durina service. The Staff has imposed more restrictive criteria for preventive plugging (including the plugging of tubes restricting passage of a.610 inch probe) at several units which have experienced extensive denting.
To sleeve a dented tube which would othenvise be plugged would severely limit the outer diameter (0.D.) of the sleeve which could be
9 inserted into the tube to less than.540 inches.
(Bycomparison,the0.D.
of the Point Beach sleeves is.740 inches). Large scale sleeving with 0.D.s less than.540 inches would result in a substantial reduction in flow area compared to the Point Beach sleeves.
Because denting would tend to occur at many or all of the seven support plate locations in addition to the tubesheet location, as many as eight different sleeves might have to be installed into each tube. This would add considerably to the time, effort, complexity, cost, and occupational exposure involved in performing large scale sleeve repairs.
In addition, it is not clear that sleeving would constitute an effective long term repair to an extensive denting problem. Note that the Point Beach sleeves are believed to be more resis-tant than the original tubes to stress corrosion cracking which is the problem which these sleeves are intended to address.
As previously mentioned, the Staff has no information regarding whether denting is present at the tubesheet location at Point Beach Units 1 and 2.
However, even if present, the diameter could not have been reduced to any less than.740 inches and still permit insertion of i
the sleeve.
If denting is present and continues to progress to the point where significant denting of the sleeve occurs, this condition will be detected during routine eddy current inspections which are periodically performed on the tubes, just as it would be detected in an unsleeved tube.
Finally, operating experience has shown that where denting has resulted in leaks, the leaks have been small and stable. Restrictive limits on allowable primary to secondary leakage in the Plant Operating License provide added assurance of safe operation.
4 t
I swear that the infonnation contained in this affidavit is true and correct to the best of my knowledge.
i; i
Q A
^
j Enunett L Murph Subscribed and sworn to before me this 14th day of April,1982
~Y W & r:t i
/M Notary Public' fly Comission expires: (-/f/ /,
/
/ff),
/
fl i
l
?
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
)
)
Docket Nos. 50-266 WISCONSIN ELECTRIC POWER COMPANY
)
50-301
)
(Point Beach Nuclear Plant,
)
(Repair to Steam Generator Tubes)
Units 1 and 2)
)
CERTIFICATE OF SERVICE I hereby certify that copies of "NRC STAFF RESPONSE TO LICENSING BOARD'S MEMORANDUM AND ORDER DATED APRIL 7, 1982" and." AFFIDAVIT OF EMMETT L. MURPHY" in the above-captioned proceeding have been served on the following by desposit in the United States mail, first class, or, as indicated by an asterisk, through deposit in the Nuclear Regulatory Commission's internal mail system, this 14th day of April, 1982:
Peter B. Bloch, Chairman
- Bruce Churchill, Esq.
Administrative Judge Gerald Charnoff, Esq.
Atomic Safety and Licensing Board Shaw, Pittman, Potts & Trowbridge U.S. Nuclear Regulatory Commission 1800 M Street, N.W.
Washington, DC 20555 Washington, DC 20036 Dr. Hugh C. Paxton Atomic Safety and Licensing Board Administrative Judge Panel
- 1229 - 41st Street U.S. Nuclear Regulatory Commission Los Alamos, New Mexico 87544 Washington, DC 20555 Dr. Jerry R. Kline*
Atomic Safety and Licensing Appeal Administrative Judge Panel (5)*
Atomic Safety and Licensing Board U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Washington, DC 20555 Washington, DC 20555 Docketing and Service Section (1)*
Kathleen M. Falk, Esq.
Office of the Secretary Wisconsin's Environmental Decade U.S. Nuclear Regulatory Comrissiori 114 North Carroll Street Washington, D.C.
20555
- Madison, WI 53703 Francis X. Davis, Esq.
P.O. Box 355 Pittsburg, PA 15230 Barton Z. Cowan, Esq.
[
John R. Kenrick, Esq.
Ricnard G. Bachmann Eckert, Seamans, Cherin & Mellott Counsel for NRC Staff 42nd Floor, 600 Grant Street Pittsburgh, PA 15219
-