United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 73-05: Philadelphia Electric Company




                                                             IEB 73-05

                                 UNITED STATES
                           ATOMIC ENERGY COMMISSION
                     DIRECTORATE OF REGULATORY OPERATIONS
                                   REGION I
                                631 PARK AVENUE
                      KING OF PRUSSIA, PENNSYLVANIA 19406

                                        October 5, 1973

Philadelphia Electric Company                          Docket No. 50-278
Attention:  Mr. V. S. Boyer
            Vice President
2301 Market Street
Philadelphia, Pennsylvania  19101

Gentlemen:

As a result of previous information we received that your control rods could
contain inverted absorber tubes, this office notified you by letter dated
July 25, 1973, that appropriate action should be taken by you to verify proper
assembly of all control rods, including spares.  We now have additional
information that other types of control rod manufacturing defects have been
identified.

The enclosed Directorate of Regulatory Operations Bulletin No. 73-5,
"Manufacturing Defects in Boiling Water Reactor Control Rods," is sent to you
to provide you with information we received from the General Electric Company,
Millstone Point Company, Tennessee Valley Authority and Philadelphia Electric
Company concerning control rods.  This information may relate to the
performance of certain equipment at your facility(ies).  Action requested on
your part is identified in Section B of the bulletin.

                                     Very truly yours,


                                     James P. O'Reilly
                                     Director

Enclosure:
RO Bulletin 73-5
.

                                                RO Bulletin No. 73-5
                                                October 5, 1973

MANUFACTURING DEFECTS IN BOILING WATER REACTOR CONTROL RODS

We recently received information that control rods scheduled to be installed
in certain boiling water reactors contained absorber tubes installed in an
inverted position and certain other types of manufacturing defects.  Pertinent
details on this problem are contained in Section A below.  Action requested by
this bulletin is contained in Section B.

a.  Description of Problem       

While performing repairs of manufacturing defects on control rods returned to
the General Electric Company's manufacturing facility 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
problem was discovered had originally been returned from a reactor site to the
manufacturing site for inspection and repair of other types of defects (listed
below) that were identified at the Millstone 1 facility in January of 1973.

At the time of the most recent problem 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 problem.  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 number of control rods were noted 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 contain additional manufacturing defects of the types listed below:
.

-                                      2 -

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

7.  Velocity limiter roller bearing frozen

8.  Improper axial clearance of absorber tubes within sheaths


Types of Control Rod Defects or Deficiencies Identified at Millstone 1 1/

1.  Improper setting of coupling lock plug height

2.  Improper extension of lock plug shaft above nut

3.  Improper axial clearance of absorber tubes within sheaths

4.  Failure to chamfer velocity limiter casting at juncture point to sheath

5.  Improper spot welds at end of sheath and on unlocking handle cover strips

6.  Improper spot welds at end of sheath and on unlocking handle cover strips

7.  Restrictions preventing free operation of uncoupling handle

8.  Improper height of crowns of socket attachment weld


_____________________
1/ Letter from A. P. Bray, General Electric Company to Mr. E. Kruesi, Director
of Regulatory Operations, USAEC, dated April 26, 1973. 
.

-                                      3 -

B.  Action Requested of the Licensee

It is requested that you develop and implement an inspection program at the
reactor site to examine each of the control rods received at your facility. 
The inspection program should include appropriate 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 Peach Bottom 2 and Browns
Ferry 1 facilities, inverted absorber tubes or missing absorber tubes.

Within 30 days of your receipt of this bulletin, a written report should be
submitted to the cognizant Regional Office with a copy to Mr. B.H. 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 previously been submitted to the AEC on this subject that
you wish to use to satisfy any portion of the requested information, please
include appropriate references in your reply.

Page Last Reviewed/Updated Tuesday, July 23, 2013