United States Nuclear Regulatory Commission - Protecting People and the Environment

IE Circular No. 78-34 - Installation Error That Could Prevent Closing of Fire Doors


                               May 15, 1978 

MEMORANDUM FOR:     B. H. Grier, Director, Region I 
                    J. P. O'Reilly, Director, Region II 
                    J. G. Keppler, Director, Region III  
                    G. L. Madsen, Acting Director, Region IV 
                    R. H. Engelken, Director, Region V 

FROM:               Harold D. Thornburg, Director, Division of Reactor     
                      Operations Inspection, Office of Inspection and 

                    PREVENT CLOSING OF FIRE DOORS 

The subject circular is transmitted for issuance by close of business within
three days after date of this letter. The circular should be issued to all 
holders of Reactor Operating Licenses or Construction Permits. Also enclosed
is a draft copy of the transmittal letter. 

                                        /S/ Karl V. Seyfrit/for  
                                   Harold D. Thornburg, Director 
                                   Division of Reactor Operations 
                                   Office of Inspection and Enforcement 

1. Draft Transmittal Letter 
2. IE Circular 78-04 

CONTACT:  D. C. Kirkpatrick, IE 

                                                        May  , 1978        

(Transmittal letter for IE Circular 78-04, to each holder of an NRC 
Operating License or Construction Permit.) 

                                                     IE Circular No. 78-04 

The enclosed IE Circular No. 78-04, is forwarded to you for information. No 
written response is required. Should you have any questions related to your 
understanding of this matter, please contact this office. 


                                        (Regional Director) 

1.  IE Circular No. 78-04 
2.  List of IE Circulars 
      Issued in 1978 

                             UNITED STATES 
                         WASHINGTON, D. C. 20555 

                              May 15, 1978  

                                                     IE Circular No. 78-04 


During a quality assurance audit, Georgia Power Company personnel discovered
three types of installation errors on sliding fire door closers at the Hatch
Nuclear Station that could have prevented the functioning of the doors. 

The mechanism involved are D and H Pyromatic door closers manufactured by 
Mesker (see attached drawing). Each unit is powered by a suspended weight 
which rotates a pulley arrangement to draw the fire door closed. Closure is 
normally prevented by a fuse link cord which acts through a lever arm. This 
device, called the "fuse link anchor hook," prevents rotation of the 
pulleys, unless the fuse links are severed by fire. 

The first improper installation was the replacement of the combustible fuse 
cords by "S-Hook" type chain. The replacement was necessary due to random 
failures of the original fuse link cord. However, the cord (or chain) passes
through an opening in the case containing the mechanism, and the S links 
tended to spring open and catch on the edges of this opening. This problem 
was aggravated in some instances by the lack of guide bushings which are 
normally installed to facilitate the passage of the chain through the 

Another error discovered was the mispositioning of the fuse link anchor 
hook. Following severance of the fuse link, the pulleys rotate clockwise and 
a correctly installed anchor hook is rotated through an angle that permits 
the terminal eye on the end of the fuse link cord to fall free. This 
prevents the cord (or chain) and the remains of the fuse link assembly from 
becoming entangled in the rotating mechanism. However, some anchor hooks 
were found to be installed with the curved section extending to the left 
(relative to the front view shown). This position can cause the terminal eye 
to remain hooked during rotation, instead of falling free. These errors 
actually caused the jamming of fire door closers during tests that followed 
their discovery. 

The corrective actions were to replace the "S" type chain with flat sash 
chain, install the missing bushings and to correctly orient the fuse link 
anchor hooks. 

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IE Circular No. 78-04                                   May 15, 1978       

It is recommended that all holders of reactor operating licenses and 
construction permits determine if any fire door closers of this type are 
installed in their facility(ies). If this is the case, it should be verified
that they are installed in accordance with the manufacturers design and that
improper installations, such as described herein, do not exist. 

This circular is being distributed for information, and no reply is 
requested. If you require any additional information regarding this matter, 
please contact the director of this NRC Regional Office. 

Drawing No. R-4174 
  D&H Pyromatic Door Closer  

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