ML20085G571
| ML20085G571 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Browns Ferry |
| Issue date: | 10/04/1973 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| Shared Package | |
| ML20085G474 | List: |
| References | |
| IEB-73-05, IEB-73-5, NUDOCS 8308290147 | |
| Download: ML20085G571 (5) | |
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()gulatoryOperations i
Bulletin No. 73-5 i
Date: October 4, 1973 l
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HANUFACTURING DEFECTS IN BOILING WATER REACTOR CONTROL RODS 1
We recently received information that control rods scheduled to be
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installed in certain boiling water reactors contained absorber tubes installed in an inverted position and certain other types of manu-4 i
facturing defects.
Pertinent details on this problem are contained in Section A below. Action requested by this bulletin is contained in Section B.
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j A.
Description of Problem I
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While performing repairs of manufacturing defects on control rods returned to the Concral Electric Company's manufacturing facility i'
at Wilmington, North Carolina, it was discovered that some of the control rod neutron absorber tubes had been installed in an inverted condition. Subsequent information received from the General Electric Company indicates that the problem of inverted absorber tubes is widespread and all control rods manufactured at the Wilmington, North Carolina site are suspect. The control rods in which this l
problem was discovered had originally been returned from a reactor i
site to the manufacturing site for inspection and repair of other i
types of defects (listed below) that were identified at the Millstone 1 facility in January of 1973.
8308290147 731107
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PDR ADOCK 05000259 S
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At the time the most recent prob 1cm was identified, control rods from several boiling water reactors had been inspected to determine if they contained defects of the types noted at Millstone 1, repaired, and returned to the reactor sites without noting the inverted absorber tube prob 1cm.
Two facilities in this category were Peach Bottom 2 and Browns Ferry 1.
Inspections of control rods for these two facilities were performed at the reactor sites and %30 percent of the total num-ber of control rods were ncted to contain inverted absorber tubes or inverted sheaths (each containing 21 absorber tubes).
Subsequent shipments of control rods from the manufacturing site, provided as replacements for the control rods containing inverted absorber tubes and sheaths, were inspected upon arrival at these sites and noted to ccntain additional manufacturing defects of the types listed below:
Types of Control Rod Defects or Deficiencies Identified at Peach Bottom 2 and Browns Ferry 1 1.
Bent and bulged sheaths 2.
Cracking in velocity limiter 3.
Improper operation and alignment of unlocking handle 4.
Failure to chamfer velocity limiter casting at juncture point to sheath 5.
Tack weld missing on coupling handle and unlatch track 6.
Inspectors stamp not present on sheath
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7.
Velocity limiter roller bearing frozen 8.
Improper axial cicarance of absorber tubes within sheaths Types of Control Rod Defects or Deficiencies Identified at 1!
Millstone 1 1.
Improper setting of coupling lock plug height 2.
Improper extension of lock plug shaft above nut 3.
Improper axial cicarance of absorber tubes within sheaths 4.
Failure to charfer velocity limiter casting at juncture point to sheath 5.
Improper spot welds at end of sheath and on unlocking handle cover strips 6.
Improper tack welds in coupling locking shaf t to nut, nut to handle, and valve to handle 7.
Restrictions preventing free operation of uncoupling haadle 8.
Improper height of crowns of socket attachment veld B.
Action Requested of the Licensee It is requested that you develop and implement an inspection program the reactor site to examine cach of the control rods received at at your facility. The inspection program should include appropriate 1/ Letter from A. P. Bray, General Electric Company to Mr. F. E. Krucsi, Director of Regulatory Operations, USAEC, dated April 26, 1973.
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measurements and tests to verify that your control rods are properly manufactured and do not contain defects of the types identified at the Millstone 1 facility in January 1973, defects of the types recently identified at the !!111 stone 1 facility in January 1973, defects of the types recently identified at the Peach Bottom 2 and Browns Ferry 1 facilities, inverted absorber tubes or cdssing absorber tubes.
Within 30 days of your receipt of this bulletin, a written report should be submitted to the cognizant Regional Of fice with a copy to Mr. B.11. Grier, Assistant Director for Construction and Operation, Directorate of Regulatory Operations, USAEC, Washington, D. C., 20545, providing a description of your inspection program and your schedule for conducting this program.
Within 30 days of completion of your inspection program, a written report should be submitted to the same addressees listed above providing the inspection results. Please include in this response, a description of the corrective actions taken or planned and the date of scheduled completion of your corrective actions.
If similar or other defects with your control rods are identified, they should be promptly reported to the cognizant Regional Office by telephone.
If information has previous 1v been subultted to the AEC cn this subject that you wish to use to satisfy any portion of the requested information, please inclinle appropriate references in your reply.
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Directorate of Regulatory Operations Bulletin 73-5 DISTRIBUTION:
Deputy Director, F0, RO Assistant Director for RE&MP, RO Assistant Ditector for C60, RO Branch Chief, FS&EB, R0 Assistant Director for Plans and Programs, RS Director, L Deputy Director for Reactor Projects, L Deputy Director for Technical Review, L Assistant Director for Boiling Water Reactors, L (3 cys)
Assistant Director for Pressurized Water Reactors, L (3 cys)
Assistant Director for Operating Reactors, L (3 cys)
Assistant Director for Environmental Projects, L (3 cys) l R. F. Fraley, ACRS Files l
DR Central Files cc: Letter addressed to Licensee w/ enc 1 w/o distribution list NSIC R. L. Shannon, OIS PDR LPDR
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