United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 83-40: Need to Environmentally Qualify Epoxy Grouts and Sealers

                                                            SSINS No.: 6835 
                                                            IN 83-40       

                                UNITED STATES
                           WASHINGTON, D.C. 30555
                                JUNE 22, 1983

                                   GROUTS AND SEALERS 


All nuclear reactor facilities holding an operating license (OL) or 
construction permit (CP). 


This information notice is intended to alert licensees to potential 
degradation of epoxy formulations by heat and radiation. No specific action 
or response is required. 

Description of Circumstances: 

At Watts Bar, TVA reported in September 1981 that two epoxy grouts, used to 
install various anchor bolts inside the containment building, had been 
specified by trade name without consideration of the thermal aging and 
radiation environment. In a followup report dated September 1982, TVA 
reported that tests at temperatures up to 160F had been performed, and 
that the compounds had shown significant loss of strength at temperatures 
above 120F. 

Contrary to usual IE practice, the trade names of the products are not being
disclosed, because we believe that many other similar products may have 
similar or poorer thermal characteristics. 

In recent years, epoxy products have achieved widespread acceptance in 
concrete construction and repair. ASTM and ACI standards have been issued, 
but these standards address the use of epoxy in normal construction and 
repair, with temperatures limited to those ordinarily caused by changes in 
weather. For example, ASTM C 883 calls for test cycling between 73F and
125F; ASTM C 884 in a different test calls for cycling between 73F
and -6F. 

One reference book lists 63 types of epoxy resins and 62 chemical groups 
which can be used for curing the resins. Further, there is a wide variety of
fillers, accelerators, and other ingredients used in compounding the 
products. As a result, a wide variety of products can be formulated to the 
desired end-use characteristics. 


                                                              IN 83-40     
                                                              June 22, 1983 
                                                              Page 2 of 2  

Some general rules of organic chemistry can be applied in designing an epoxy
compound with the desired physical and chemical Characteristics, such as 
strength at elevated ,temperature and resistance to radiation damage. 
However, full confidence in the results can only be achieved by product 

Another characteristic which needs to be considered is the relatively low 
creep strength of epoxies. Where anchor bolts are bedded in epoxy grout, and
tensioned to any appreciable preload, it may be important to periodically 
verify that the preload has not been lost by creep in the grout. 

TVA has halted the use of epoxy grout, and is in the process of analyzing 
individual past uses to determine what, if any, corrective actions are 

No specific action or reply is required, If you have any questions regarding 
this matter, please contact the Regional Administrator of the appropriate 
NRC Region Office, or this office. 

                                   Edward L. Jordan Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contact:  J. B. Henderson, IE

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