ML20214L932

Forwards Results of Analysis of Dose Rate Underneath TMI-2 Reactor Vessel.Analysis Concludes That Dose Rate Profiles Measured in Mar 1986 W/Miniature Ion Chambers Can Be Correlated to Calculations Re Cesium Contamination

ML20214L932
Person / Time
Site:	Three Mile Island
Issue date:	05/21/1987
From:	Standerfer F GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20214L934	List: ML20214L932 ML20214L947
References
4410-87-L-0068, 4410-87-L-68, NUDOCS 8706010124
Download: ML20214L932 (4)

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GPU Nuclear Corporation Nuclear = ,o r s r 8oe Middletown, Pennsylvania 17057 0191 717 944 7621 TELEX 84 2386 Writer's Direct Dial Number:

(717) 948-8461 4410-87-L-0068 Document ID Ol83P May 21,1987 US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

Dear Sirs:

Three Mile Island Nuclear Station, Unit 2 (TMI-2)

Operating License No. DPR-73 Docket No. 50-320 Reactor Pressure Vessel Integrity CPU Nuclear letter 4410-87-L-0013, dated January 19, 1987, advised that Babcock and Wilcox (B&W), the THI-2 reactor designer, had been requested to conduct a review of the dose rate profiles obtained from the cavity underneath the Reactor Vessel (RV). Those dose rate profiles were reported in Reference 1.

B&W has concluded their review and provided the results of their analysis (Reference 2). A copy is attached for your information. The analysis concludes that the dose rate profiles measured in March 1986 with miniature ion chambers can be correlated to calculations which assumed cesium contamination sources without assuming there is fuel beneath the RV. The contamination sources considered include the bathtub ring on the Reactor Building (RB) basement wall, RB wall contamination, RV insulation contamination, dissolved activity in basement water, and contamination on pipe surfaces.

Consistent, with the findings of the Burns and Roe (B&R) analysis, the B&W analysis concludes that the correlation of dose rate profiles and assumed contamination sources does not provide conclusive evidence as to the presence or absence of fuel below the RV. In that regard, GPU Nuclear wishes to reiterate that the preponderance of the evidence provides no basis to doubt the integrity of the lower head. Thus, CPU Nuclear plans to continue defueling activities.

jtod 8706010124 870521 a subsidlary of the General Public Utilities Corporation I PDR ADOCK 05000320 BI P PDR

Document Control Desk May 21, 1987 4410-87-L-0068 As noted in our letter of January 19, 1987, GPU Nuclear plans to perform a gamma spectrometer survey of the cavity under the RV, as recommended by B&R, as part of the fuel accountability effort on a "non-interfering basis" with defueling. Those survey results will be provided to you as they become available.

Sincerely, M.,

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F. R. Standerfer Director, TMI-2 FRS/JJB/eml Attachments cc: Regional Administrator, Region 1 - W. T. Russell Director, TMI-2 Cleanup Project Directorate - Dr. W. D. Travers President, Burns and Roe Company - W. R. Cobean i

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Document Control Desk May 21, 1987 4410-87-L-0068 REFERENCES

1. TMI-2 Technical Bulletin 86-25 dated May 2,1986, Revision 0, " Gamma Scaming of the Cavity Under the Reactor Vessel."

2. " Babcock and Wilcox Analysis of Dose Rate Under TMI-2 Reactor Vessel,"

Prepared by N. L. Snidow and S. O. King, dated April 13, 1987, B&W Document No. 51-1167938-00.

ATTACHMENT 35 Pages 4410-87-L-0068 BWNP 2003216 (10/86 Ba np, en (k- DOCUMENT RELEASE NOTICE (DRN)

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mNTE0 NAVE, N.L. Snidow ,pRiNTE0 NAVE 3 Donald A. Nitti