ML20247E147
| ML20247E147 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 07/20/1989 |
| From: | Morris K OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-1344 GL-89-08, GL-89-8, LIC-89-635, NUDOCS 8907260095 | |
| Download: ML20247E147 (4) | |
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,e Omaha Public Power District 1623 Hamey Omaha, Nebraska 68102 2247 402/536 4000 July 20, 1989 LIC-89-635 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station PI-137 Washington, DC 20555
References:
1.
Docket No. 50-285 2.
Letter from.KRC (J. G. Partlow) to OPPD (K. J. Morris) dated May 2, 1989 Centlemen:
SUBJECT:
Response to Generic Letter 89-08 " Erosion / Corrosion - Induced Pipe Wall Thinning" Generic Letter 89-08 (Reference 2) requested assurances that a program consisting of systematic measures to ensure that erosion / corrosion does not lead to degradation of single-phase and two-phase high-energy carbon steel systems has been implemented.
Information was also requested on whether or not a long term erosion / corrosion program based on a NUMARC or another equally effective program has been or will be instigated.
If a long term program has not been started, then a scheduled implementation date is required.
The following discussion, along with referenced procedures outlines Omaha Public Power District's (OPPD) erosion / corrosion control program as it exists to this point, and also describe:: future plans for this trea.
1987 Erosion / Corrosion Control _.frocram During the 1987 refueling outuge at Fort Calhoun Statio.), 188 piping components were inspected under a Preventive Maintenance Procedure PM-PIPE-1, " Ultrasonic Inspection of Station Piping." High energy single and two-phase carbon steel systems were evaluated based on Electric Power Research Institute (EPRI) report NP-3944, current N^.C Information Notices and Bulletins, the experiences of other plants and engineering judgernnt.
PM-PIPE-1 also enabled wear rates to be calculated. These wear rates were used to calculate the number of cycles remaining before design minimum wall thickness would be approached.
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Page 2 Please note that the number of components being inspected from outage to outage varies because of the dynamic nature of this program.
Initial numbers of components inspected were high and as OPPD gains baseline data and experience it will add or delete components from the program as necessary to ensure it has i
identified all susceptible components.
1988 Erosion / Corrosion Proaram During the 1988 outage, continued input from NRC Bulletins, other plant experiences, a NUMARC Technical Subcommittee Working Group Report on " Piping Erosion / Corrosion" and the EPRI "Chec" computer program were assimilated into the erosion / corrosion control program.
The EPRI "Chec" computer program
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incorporates parameters such as moisture content, water chemistry, fluid i
velocities and pipe geometries, material, and temperature in selecting susceptible single phase areas. The "Chec" program was also used to rank susceptibility to erosion / corrosion based on wear rates, time to minimum wall, location and component geometries.
During the 1988 outage at the Fort Calhoun Station, 104 components were inspected, 57 single-phase, and 47 two-phase. The components inspected during the 1988 outage were gridded in accordance with Quality Department Procedure QDP-20 which established greater consistency for identification of test locations, and also specified grid dimensions for particular pipe sizes.
The procedares utilized for the thickness measurements takcn during the 1988 outage identifies equipment to be used, calibration of equipment for the wall thicknesses to be measured, and surface preparation requirements.
Evalua-tion / interpretation of results and necessary reports were also addressed. The test results are magnetically stored and placed onto a computer for processing. The procedure requires personnel to be qualified to a minimum of ASNT SNT-TC-1A Level 2 UT in ultrasonics to be involved in data acquisition.
The aforementioned Quality Department procedures along with PM-PIPE-1 comprised the backbone for identifying and measuring the erosion / corrosion rates during the 1988 outage.
Future Plans for the Erosion,'orrosion Proaram j
l Since completion of the 1988 outage, information from NUREG-1344, issued in 1
April 1989, and an erosion / corrosion data handling workshop held May 2, 1989, has become available.
This new information will be incorporated into our l
program for use before our next scheduled refueling outage in the spring of 1990. Another change planned for the 1990 outage will be the use of ultrasonic j
equipment capable of not only detecting minimum wall thickness, but indicating more accurately where the m41 mum wall thickness is located by utilizing the back wall reflection " walk." The new ultrasonic instruments will also evaluate l
areas within a grid rather than solely the areas at the intersection of grid j
networks as performed during the 1988 outage.
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U. S.' Nuclear Regulatcry Commission LIC-89-635 Page 3 OPPD believes that the program it presently has in place as described in the above discussions, plus planned enhancements noted below provides assurance that erosion / corrosion will not lead to degradation of single-phase and two-phase high-energy carbon steel piping systems.
A long term erosion / corrosion control program based on NUMARC criteria is scheduled to be in place before the 1990 refueling outage.
The charter for this erosion / corrosion control program has been written and comments are currently being evaluated.
This response is.being submitted under oath in accordance with the reporting requirements of Generic Letter 89-08.
If you have further questions on this matter or require additional information, please contact me.
Sincerely, K.
. Morris Division Manager Nuclear Operations KJM/pje c:
LeBoeuf, Lamb, Leiby & MacRae R. D. Martin, NRC Regional Administrator A. Bournia, NRC Project Manager P. H. Harrell, NRC Senior Resident Inspector
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION i!.
In the Matter of
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Omaha Public Power District
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Docket No. 50-285 (Fort Calhoun Station
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Unit No. 1)
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AFFIDAVIT K. J. Morris, being duly sworn, hereby deposes and says that he is the Division Manager - Nuclear Operations of the Omaha Public Power District; that as such he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached information concerning the response to NRC Generic Letter 89-08; that he is familiar with the content thereof; and that the matters set forth there'in are true and correct to the best of his knowledge, information, and be1ief.
/ 7n74:7 K.'fj/Mo/ris' ' l i Division Manager Nuclear Operations STATE OF NEBRASKA)) ss COUNTY OF DOUGLAS) Subscribed and sworn to before me, a Notary Public in and for the State of Nebraska on this Ao day of July,1989. ~ amammaaredeene A mt na m esma L '~ Notary Public _ __}}