Text

Request for Approval of Release Criteria for General Atomics Triga Reactor Facility
	ML15362A506
Person / Time
Site:	General Atomics
Issue date:	12/18/2015
From:	Asmussen K E; General Atomics
To:	Vaaler M G; Reactor Decommissioning Branch
References
	Download: ML15362A506 (1)
	v • d • e

38/67- 4706December 18, 2015Marlayna G. Vaaler, Project ManagerReactor Decommissioning BranchDivision of Decommissioning, Uranium Recovery, and Waste ProgramsOffice of Nuclear Material Safety and Safeguards Docket Nos: 050-00089 and 050-00163 (R-38 and R-67, respectively)

Subject:

Request for Approval of Release Criteria for General Atomics TRIGA Reactor Facility

Dear Ms. Vaaler,

As you are aware, General Atomics (GA) has been conducting activities in furtherance of thedecontamination and decommissioning its TRIGA Reactor Facility where GA's Mark I and Mark F non-power research

reactors, R-38 and R-67 respectively, are located on GA's site.GA is now in the process of obtaining information about the extent and level of activation in thestructural concrete comprising the biological shield, reactor pool and fuel storage canals associated withits reactors.

In addition, GA is also acquiring information with regard to whether the soil beyond(outside) the biological shield has been activated and/or contaminated; and, if so, to what extent and towhat levels.In planning for the final stages of decommissioning, it is important to know what levels of residualactivity (for each individual nuclide of interest) are acceptable to the U.S. Nuclear Regulatory Commission (NRC:) for release of GA's TRIGA Reactor Facility (including the associated land area) tounrestricted use. Those levels (i.e., release criteria) are the primary factors in determining the volume ofconcrete that will need to be removed from the reactor structure and the amount of contaminated oractivated soil that may need to be excavated.

That information will, in turn, drive the scope of thedecontamination

efforts, including the extent of building demolition

required, the volume of low-level waste that must be packaged and shipped off-site for disposal, numerous and various other associated D&D costs, and the schedule for completing the decommissioning of GA's TRIGA Reactor Facility.

Historically, GA has obtained the release of its facilities and land areas to unrestricted use based uponmeeting clear release criteria provided in NRC-approved decommissioning plans. Examples include GA'sHot Cell Decommissioning Plan (Ref. 1) and the General Atomics' Site Decommissioning Plan (Ref 2).Both of these plans contain tables with soil and concrete rubble release criteria (in pCi/g) for specificindividual radionuclides of interest.

In particular, see the Attachment to this letter which was takenfrom Section 6.2.1 "Release Criteria" of Section 6.2 "Soil Sampling Plan" of Reference 2.With only one exception, the above NRC-approved plans and the consistent set of release criteriacontained therein (e.g., Attachment) have been the basis for the release to unrestricted use of everybuilding

(~35) and all land areas comprising GA's original site ("~415 acres). The only exception beingGA's TRIGA Reactor Facility (and associated licensed land area) located in the middle of its site.3550 GENERAL ATOMICS COURT, SAN DIEGO, CA 92121-1"122 P0OX56,SADEGC926-68 (8 4-30(858) 455-3000 Marlayna G. Valaar December 18, 201538/67-4706 Page 2Unfortunately, GA's NRC-approved TRIGA Reactor Facility Decommissioning Plan (July 1999) does notcontain a table of isotope specific release criteria applicable to activated concrete in the reactor pitconfiguration or to activated or contaminated soil (for example the soil behind the biological shield).

Rather the criteria are expressed as acceptable surface contamination levels. (floors and walls)and exPosure rates in. uR/hr at one meter above the surface.Consequently, GA is hereby requesting that the isotope specific release criteria (e.g., in pCi/gm)previously approved by the NRC for the release of facilities and land areas comprising GA's site (e.g.,those criteria contained in Reference

2) be approved for use in obtaining the release of its TRIGAReactor Facility (including land areas within the TRIGA licensed boundary);

e.g., by incorporating thosecriteria by reference into GA's TRIGA Reactor Facility Decommissioning Plan.If you have questions or desire additional information regarding this request, please contact me atkeith.asmussen@ga.com or (858) 455-2823, or Paul Pater at paul.Dater@ga.com or (858) 455-2758.

Very truly yours,Keith E. Asmussen, Ph.D., DirectorLicensing, Safety and Nuclear Compliance ReferenCes:

1) "General Atomics Hot Cell Facility Decommissionng Plan," dated November 1995;Approved by NRC on May 1, 1996 ; additional supplemental information datedNovember 20 and 30, and December 18, 1995 approved by NRC letter dated January 29,1997.2) "General Atomics' Site Decommissioning Plan," September 1996, revised December1996, Revised April 1997 and Revised January 1998. Approved by NRC per SNM-696License Amendment No. 45 dated April 29, 1998

Attachment:

Table 6-2 "Soil and Concrete/Asphalt Rubble Release Criteria" taken from GeneralAtomics' Site Decommissioning Plan (Taken from Section 6 of Ref. 2 of this letter)

Attachment.38676 38/67-4706 Table 6-2--Soil and ConcretelAsphalt Rubble Release Criteria' Isotope' Release Criteria Based upon Release Criteria Based uponExternal Exposure Limitations Internal Exposure Limitations

_____ ,________(pCi/g)

_.~lg137Cs 150!m(:s*1 94Nb 7.53790Sr "__ _""___'800__

__23Bpu27-2'pu 27__ __ _ _ __ _ _ __ _ _2*pu 4326_____________

________________

242Pu ""_ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _" _ _ _ _ _ _ _Ui~m 254])epetedUraium

.......353Enriched Uranium 30sTrhorium 2Th & "sTh) --______________

0'The release criteria shown in tflS tanie WitnOUt annotation ny Ioootfles s, or 't were t~la..u-aLu uy licensee using RESRAD version 5.18 adhering to the same assumptions that were provided in thecorrespondence listed in note 2, below. This corresponds to conservative calculation of the homogenous concentration of an isotope in the soil that by itself would give approximately 10 .zR/hr external exposurerate above background for the maximum year of exposure.

It is the licensee's intent to apply criteria fromthis table to concrete,

asphalt, or similar construction media materials that have been ground to a coarserubble. These criteria were approved by the NRC for the Hot Cell Decommissioning project by letter datedMay 1, 1996, Robert C. Pierson to K. E. Asmussen.

2 These release criteria are based upon past precedent through NRC and State of California approved releaselimits for the GA site. See Correspondence K. E. Asmussen to W. T. Crow, dated October 1, 1985,correspondence identification 696-8023,

Subject:

"Docket 70-734: Plan for Obtaining Release of CertainAreas to Unrestricted Use."SThese release criteria are based upon past precedent established by NRC through NRC Policy IssueSECY-81-576, dated October 5, 1981l,

Subject:

"Disposal or on-site storage of residual thorium or uranium(either as natural ores or without daughters present) from past operations."

SNumbers were established using the most limiting of lung dose (20 mrernyr) or bone dose (60 mrem/yr) using DoseConversion Factors from NURlEGICR-0150, Volume 2, with an alpha quality factor of 20, where applicable, lungmass of 580 grams, and AM~AD of 1.0.For enriched

uranium, CIA shall determine the U-234:U-235 ratio by uranium isotopic analysis and then use gammaspectroscopy results of U-235 to demonstrate compliance with the release criteria for enriched uranium.