ML071720282

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Yankee Nuclear Power Station, Technical Basis Document for Background Sr-90 in Soil, Rev. 1
ML071720282
Person / Time
Site: Yankee Rowe
Issue date: 06/22/1998
From: Cumming E
- No Known Affiliation
To:
- No Known Affiliation, NRC/FSME
References
RP 98-72
Download: ML071720282 (5)


Text

MEMORANDUM To: File Date: June 22, 1998 From: Edward Cumnming *' File:. RP 98-72

Subject:

Technical Basis Document for Background Sr-90 in Soil, Rev. I

1. Memorandum RPG 98-01, Rev. 1, C.B. Martel to E.M. Heath, "Background Strontium-90 Concentration irt Soil." dated June 18. 1998.
2. Memorandum RPG 98-011, C.B. Martel to E.M. Heath, "Background Strontium-90 Concentration in Soil," dated May 29, 1998.
3. Procedure AP-8800. Rev. 2. "Final Status Survey Organization. Training and Technical Basis Documents."

This memorandum, along with the attached DE&S memorandum (Reference 1), constitutes a Technical Basis Document (TBD) for background concentrations of Strontium-90 in soils

  • surrounding the Yankee Nuclear Power Station. The attached DE&S memorandum is a revision to the original DE&S memorandum (Reference 2). and contains corrections to several typographical errors. Preparation and review have been done in accordance with the TBD requirements of Procedure AP-8800 (Reference 3).

cc: FSS TBD File RP File S.Robert J.Thompson 4 B.Yetter E.Heath G.Babineau K.Heider K.Corbett D.Thideau

4~t MEMORANDUM DE&S - BOLTON To -E-.M. Heath Date June 18. 1998 Group # RPG 98 11 Rev. I From C. ]B, Ma-tel W.O.# 00468.00.0004.16.00000 Subject _B¢ackgrnd Strontium-90 Concentration in Soil .MAJ A13.01.08 RT 07.C02.018 Fie# SR90BACI.WPD Reference

1. YRC-l 180, "B3ckfround Co9ncentrations of Cesium- 137 in Soil and Sediment to Sutnoxt

" PS.- 2/98

2. YRC-1 179, "Yankee Rowe Site-Svecific Derived Concentration Guideline Vaues for Residual Radioactivity in Soil." 3/98
3. YAEL Procedure 368. "Determination of Strontium-89, 90 in Environmental Media via Cerenkov Counting," Rev. 4, 7n7/97.
4. YNPS License Termination Plan, Appendix A. "Final Status Survey Plan for Site SRelease,"Rev. 1, 5/97
5. NUREG-5849. "Manual for Conducting Radiological Surveys in Support of License Termination," USNRC. 3/92 Puroose and Backaround The purpose of thi!. memo is to present a background concentration value for Strontium-90 in soils related to deconmhissioning work at the Yankee Nuclear Power Station (YNPS). This value is specifically for use in support of the Final Status Survey at the YNPS. Like Cesium-137, Strontium-90 is a rndionuclide that is present in background, and which was also produced and released to the environment by operations at YNPS. 'A background value for Cesium-137 is the subject of another report (Reference I) entitled, "Background Concentrations in Soil ind Sediment to Support the Yankee Nuclear Power Station Decommissioning Project."

The Strontium-90 value presented is calculated based on guidance in NUREG-5849 and is intended as input to help establish that radioactivity release limits are met for any residual radioactive materials remaining on-site after decommissioning. This regulatory guidance establishes a method to determine values for the background level of a given radionuclide by averaging results of sample analyses and establishing with 95% certainty, that the calculated background level for a radionuclide is correm 0

,,-N I

Heath. EF June l. 1998 Page 2 The number of samples required to provide a valid aventae value is determined by a statistical procedure. For a given number of samples collected, a mere radionuclide cratLranion value if valid if the 95% upper klvel bound of variations in individual analyses results we less dan 10%

of the Guideline Value (GLV) used for Final States Survey.

Methodology Soil samples that were analyzed for Strontium-90 wre selected from those previously collected and analyzed for Cesiu'n-137. as described in Reference I. The rationale for the location from which the &oilsampks were obtained. the th usedtooltthe soil, and its pepartin for analysis, is presented in Reference I. Strontium analyus werv performed on 30 soil samples selected from four background reference locations. Selection wasmade to tha saples were reprcscntadve of each background ea.

For Suontium analyses the process for soil sample prepation was diffeetm from that done for samples analyzed for Cesium- 137. Aliquots of soil were taken from those samples which had been &wid and bornognized by the Duke Engineering & Services Lab~orany for the Cesium- 337 analyses. The aliquots of soil were processed and analyzed according to Reference 3. The 95%

upper level bound on the avenge concentration was calculated as descn'bed in Section 52.3 of Reference 4. using Equation 5-4.

Results and Conclusions Results of the analyses we presented In the attached Table. The avenge Str*oium-90 concentration for the 30 sanples is 0.274 +/- 0.3 10 pCi/gm The OLV for Stontium-90 that will be applied to the Final States Survey at YNPS is 5.7 pCi/lm (Referan 2). The 95% upper bound on the aveBage CW6antratlon Is 6.3% of the OLV. which Is la than the 10% pruarted by NUREG-*349 (Reference 5) for silnificanc Therefo, o Amher soll sumples w requiral to further refine this vaije sincethe variatons in background am n significan and weed ano be det-rmined.

PF.pars by C. B.Martel

.lcah. E.

Junt 18. 1998 Pagc 3 Attachment c:

J. Gramnt R. Marc*lo J. Jacobson P. Littlefield D. McCurdy W. Riethle E. Cumming F. ,eliml E. Dayotas (EED/SC Fie)

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9

$Vwtronftlu Conwwitra hiBackgrmxd In Soft at YNPS I sample t4& pCgm TB-OIA 0.235 TS-IA TS-.12A -0.01


"TB-14A*I TB-ISA o4.o49 TS-16A 0244Z TS-20A 0.3267 TS-OIB .0.18 1 T8-118 TS-128 -0.02 TS-158 40.148 TS-18 0.181V TS-178 0.884,-,

TS-168 0.A

  • T7.138 -0.02 T7-208 -0.002 TS-11C 0.624 TS-18C 0.072 V TS-17C -403 4

TS-14C 0.496 TB-SOC TS-12C 0857 0371

- 1"I o,/ý TS-13C 0,413 i

1".*~-3~_

44 5- IID ' II /TS-20C _

TS o.

TB. 0 0.640 ,------ 7 (#

o~os2 ,0 IO j) ___ TB-lID 0.75 TS-13D OA49 I 'T.140 0.173 TS-ISO 0.148 TS-160 0.506

- .' Ave 0.274 SD 0.310 99% bvs D upp er bo.,osUo

  • 41)