United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 74-010B: Failures in 4-Inch Bypass Piping at Dresden-2



BL74010B 

                              UNITED STATES 
                      NUCLEAR REGULATORY COMMISSION 
                         WASHINGTON, D. C. 20555. 

                               JAN 24 1975 

J. P. O'Reilly, Director, Region I 
N. C. Moseley, Director, Region II 
J. G. Keppler, Director, Region III 
E. M. Howard, Director, Region IV 
R. H. Engelken, Director, Region V 

IE BULLETIN NO. 74-10B - FAILURES IN 4-INCH BYPASS PIPING AT DRESDEN-2 

The subject Bulletin should be dispatched for action to all BWR facilities 
of jet-pump design with operating license by close of business today. 

The Bulletin should also be dispatched for information to all other BWR 
facilities with operating license or construction permit and to all PWR 
facilities with operating license no later than close of business on January
27, 1975. 

The text of the Bulletin and draft letters to licensees are enclosed for 
this purpose. 


                              John G. Davis, Deputy Director  
                                   for Field Operations  
                              Office of Inspection and Enforcement 

Enclosures: 
As stated  
.

(Draft letter for action to all BWR facilities of jet-pump design with 
operating license)  

                                                        IE Bulletin 74-10B 

Gentlemen: 

Enclosed is IE Bulletin 74-10B, which amends the description of the 
circumstances discussed in RO Bulletin 74-10A and requests additional 
actions by you. 

Should you have questions regarding this Bulletin or the actions requested 
of you, please contact this office. 

                              Sincerely,  


                              Director 

Enclosure: 
IE Bulletin 74-10B 

     Approved by GAO, B-180225 (R0072), clearance expires 7-31-77. Approval 
     was given under a blanket clearance specifically for identified generic
     problems. 
.

(Draft letter for information to all other BWR facilities with operating 
license or construction permit and to all PWR facilities with operating 
license.)  

                                                        IE Bulletin 74-10B 

Gentlemen: 

Enclosed is IE Bulletin 74-10B which is forwarded to you for information. No
action is required of you if you do not have a boiling water reactor of 
jet-pump design with operating license. 

Should you have questions regarding this Bulletin, please contact this 
office. 

                                        Sincerely,  


                                        Director 

Enclosure: 
IE Bulletin 74-10B 
.

IE Bulletin No. 74-10B                                     Date: 1/24/75 

FAILURES IN 4-INCH BYPASS PIPING AT DRESDEN-2
(REFERENCE: RO BULLETIN NOS 74-10, Dated 9/19/74 
AND 74-10A, DATED 12/17/74) 

DESCRIPTION OF CIRCUMSTANCES (AMENDED): 

Cracks similar to those described in RO Bulletins 74-10 and 74-10A have been
revealed during reexamination of the 4-inch bypass piping at five boiling 
water reactor facilities (including Dresden-2) since mid-December 1974. All 
the facilities are of jet-pump design. In each instance where cracks have 
been revealed, the same welds had been examined previously (during 
September-November 1974) and no cracks were revealed at that time. 

A special study group, comprised of key-technical members of the Nuclear 
Regulatory Commission staff, is currently studying the causes of the cracks 
which have been experienced. Consultants from other government agencies are 
also participating in the study. 

In the interim, pending recommendations of the Commission's special study 
group, additional actions are necessary by licensees to insure continued 
close surveillance of reactor coolant leakage. 

ACTIONS REQUESTED OF LICENSEES (AMENDED): 

For all boiling water reactor facilities of jet-pump design with operating 
license: 

1.   Upon completion of those actions described in RO Bulletin 74-10A, 
     implement the following reactor coolant leakage detection program: 

     If (within the sensitivity specified in paragraph C.5. of Regulatory 
     Guide 1.45) any reactor coolant leakage detection system indicates, 
     within a period of 4 hours or less, either an increase in unidentified 
     leakage to twice the determined normal rate of unidentified leakage or 
     an increase in the rate of unidentified leakage by two (2.0) gpm or 
     more: 

     a.   Initiate plant shutdown immediately, and 

     b.   Determine the source of increased leakage prior to resuming 
          operation. 
.

    c.   If there is evidence of leakage from the 4-inch bypass piping, 
          reexamine (by ultrasonic or other suitable volumetric inspection 
          technique), all accessible welds in the bypass piping lines. 

          (In no case, however, shall the rate of leakage exceed that 
          specified in the technical specifications without those actions 
          required by the technical specifications being taken.) 

2.   Notify this office, in writing within 10 days of your receipt of this 
     Bulletin, of your intent to implement the actions described in 1., 
     above. 
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