ML19344D227

Informs That Testing & Grouting Program Completed 800213. Estimates 86% Fill in Collar Joint.No Wall Areas Contain Continuous Collar Joint Voids

ML19344D227
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	03/05/1980
From:	Lindblad W PORTLAND GENERAL ELECTRIC CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
TAC-12369, NUDOCS 8003110565
Download: ML19344D227 (2)

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March 5, 1980 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation ATTN:

Mr.~A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Raactors U. S. Muclear Regulatory Commission Washington, D. C.

20555

Dear Sir:

In our response dated December 31, 1979 to NRC Staff Question 12 regard-ing LER 79-15, Licensee committed to testing to determine the extent of mortar fill for all double block masonry walls with VQ/It stresses greater than 7.5 psi. The extent of mortar fill in such walls was verified by drilling approximately 550 test holes randomly located in different masonry courses in each wall. All holes were drilled into the middle web of the block. (Where the wall sections were long, additional test holes were drilled in order to obtain a representative sample.) The average test sample rate was one test hole per approximately 35 ft2 of wall surface. Where void or partial void areas were found, additional non-test holes were drilled to determine the extent of the void area.

Where voids were found, holes were grouted to assure complete filling of the void area. The above-described testing and grouting program was completed on February 13, 1980.

Qualitative data obtained from the testing program indicate an average of 76 percent mortar fill in the collar joint. (This did not account for the squeeze-out at the perimeter of the blocks which would be present

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even if there were no attempt to place mortar between the blocks.)

Measurement of grout take indicated that approximately 10 percent of the total area of the walls tested was filled with grout as a result of this

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Mr. A. Schwencer March 5, 1980 Page 2 program. Therefore, on the basis of the entire program, Licensee esti-mates that there is now approximately 86 percent fill in the collar joint and knows of no wall areas where continuous collar joint voids exist for those double block walls having VQ/It stresses greater than 7.5 psi.

Sincerely, Li lad

- vice President Eng'ineering-Cons truc tion c:

Mr. R. H. Engelken, Director U. S. Nuclear Regulatory Commission Region V Mr. Lynn Frank, Director State of Oregon Department of Energy i

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