Clarification to Generic Letter 81-07 Regarding Response to NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants" (Generic Letter No. 83-42)

                               UNITED STATES 
                        NUCLEAR REGULATORY COMMISSION
                          WASHINGTON, D.C.  20555 
                                     
                              December 19, 1983

TO ALL HOLDERS OF OPERATING LICENSES, APPLICANTS FOR OPERATING LICENSES AND 
HOLDERS OF CONSTRUCTION PERMITS FOR POWER REACTORS (GENERIC LETTER 83-42) 

Gentlemen: 

SUBJECT:  CLARIFICATION TO GENERIC LETTER 81-07 REGARDING RESPONSE TO 
          NUREG-0612, "CONTROL OF HEAVY LOADS AT NUCLEAR POWER PLANTS" 

On December 22, 1980, we issued a generic letter (Generic Letter 81-07) 
regarding NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants." This
letter requested that you implement certain interim actions and provide the 
NRC information related to heavy loads at your facilities. 

As indicated in NUREG-0612, one means for complying with the criteria of 
Section 5.1 is to demonstrate that no single failure in the heavy loads 
handling equipment will result in dropping of a load as discussed in Section
5.1.6.  One acceptable means of complying with the guidance of Section 5.1 
was to meet the guidelines of NUREG-0554, "Single Failure Proof Cranes." 
However, in the course of reviewing crane designs against NUREG-0554, we 
have identified concerns of a generic nature which Indicate that NUREG-0554, 
until revised, may be deficient in assuring single failure proof cranes.  
The concerns relate specifically to assuring that a single failure in the 
electric power control system will not cause a load drop.  For example, 
during our review of the TMI-2 recovery plan, the NRC became aware that an 
electrical failure in one of the three phase power leads to the polar crane 
could possibly result in the inability of the crane to support a load and at
the same time result in failure of the brake to set. 

The purpose of this letter is to inform you of this potential problem 
related to single failure proof cranes.  This aspect of single failure proof 
cranes will be part of our review of your submittal if you took credit for a 
single failure proof crane to satisfy NUREG-0612. 

                           Sincerely, 


                           Darrell G. Eisenhut, Director 
                           Division of Licensing 
                           Office of Nuclear Reactor Regulation 





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