ML021220721
| ML021220721 | |
| Person / Time | |
|---|---|
| Site: | Saxton File:GPU Nuclear icon.png |
| Issue date: | 04/08/2002 |
| From: | NRC/NRR/DRIP/RORP |
| To: | NRC/NRR/DRIP/RORP |
| Adams A, NRC/NRR/DRIP/RORP, 415-1127 | |
| Shared Package | |
| ML021220111 | List: |
| References | |
| -nr | |
| Download: ML021220721 (17) | |
Text
SNEC Decommissioning Project NRC Public Meeting April 8, 2002
Submittal History
- April 1998 - License Amendment 15 authorizes decommissioning
- February 2000 - License Termination Plan submitted to NRC for review and approval.
- August 2000 - RAI 1 (Request for Additional Information) issued by NRC
- 27 Questions GPU responses to 20 of 27 questions accepted by NRC Remaining 7 questions carried over into RAI 3
- November 2000 - RAI 2 issued by NRC 10 Questions GPU response to 5 of 10 questions accepted by NRC Resolution of remaining 5 questions in progress
Submittal History (cont..)
- January 2001 - RAI 3 issued by NRC 7 Questions GPU responses to 4 of 7 questions accepted by NRC Currently awaiting NRC acceptance of remaining 3 questions.
- Classification of area under CV saddle (Needs updated by GPU on latest angle well installation & results of over 700 soil samples.)
- Groundwater behavior issues
- Area characterization / Kd study / dose modeling (covered in RAI
- 2)
Characterization Submittals July 2001 - Phase 1 - DSF, CV Pipe Tunnel subsurface soil, &
pavement/subpavement soil.
September 2001 - Phase 2 - SSGS, Discharge Tunnel &
Surrounding Environs January 2002 - Phase 2&3 - River Sediment, Yard Drains, & Intake Tunnel
Key Technical Support Contractor Name Technical Area
- 1. URS Subsurface dose modeling
- 2. Haley & Aldrich Hydrogeology
- 3. Argonne National Lab (ANL)
- RESRAD training
- Kd development
- 4. Dames & Moore MARSSIM training
- 5. ENERCON River sediment sampling
- 6. Shonka & Associates Large Area Surveys
6 - RAI2 Key NRC Concerns Concerns with the analyses used to develop DCGLs used for soil, concrete debris and sediments Particularly, there is insufficient basis to support the approach used for conducting the sensitivity analyses to identify key parameter and for analyzing subsurface material.
- Insufficient documentation and information to allow a clear understanding of how the analysis was done.
Concerns with transparency and reproducibility of the analysis.
RAI 2 GPU Response
- Our RAI2 responses raise numerous concerns on methodology expectations and GPU seeks to obtain further clarification from NRC.
- GPU believes we have sufficient justifications on information used for answer RAI2 questions. We agree that the information needs to be communicated more effectively to the NRC for verification.
- Recommend that NRC and GPU staffs take more time to review jointly what we have done and determine what needs to go on the docket.
GPU vs NRC Soil DCGLs (pCi/g)
Isotope GPU DCGL 3 NRC DCGL 1 2 GPUINRC Ratio
ýAm-241 18 2.1 8.6 0C-14 122.3 Cm-243 25 3.2 7.8 0m-244 39**
Co-60 3
93.81.0 Cs-1 34 5.1 5.7 0.9 Cs-137 87110.8 Eu-152.18 8.7 1.2 Eu-154 10 8
1.3 Eu-155 415**
Fe-55 2.30E+04 1.00E+04 2.3 H-3 L 1400 110 12.7 Nb-94 7.6 5.8 1.3 Ni-59 3216 5500 0.6 Ni-63 17:
100.6 Pu-2386..
.7.....
.2.7 Pu-239 1.5 2.3 0.7 P u-240 1".6**
Pu-241 11 211 72 14.2 P u-242 1
1l.6**
Sr-90 131.7 0.8 TC-99 11.4 19 0.6 U-234 1.9 13 0.1 U-235 1.9 0.29 6.6 U-238 2
0.5 4.0 Number 234) equilibrium.
- 1. Reference Federal Register: December 7, 1999 (Volume 64,
- 2. NRC DCGL values for U-235/238 account decay progeny in
- 3. Shaded areas denote primary radionuclides found at SNEC.
- No NRC DCGLs available I
1 -RAI2 Q3 Issues
"* DCGL justification for embedded piping.
"* Clarify which DCGLs (surface or volumetric) apply to releasing the CV.
"* Provide area factor calculation (SNEC Calculation
- E900-01-005) to facilitate NRC review.
"* Update volumetric area factors based on latest modeling. (Ref.)SNECCalc. #6900-02-008, -1)
2 - RAI2 Q4 Issues
"* NRC unable to duplicate surface soil DCGLs based on information submitted.
"* NRC needs to obtain electronic copies of the RESRAD input/output files.
"* Describe clearly how DCGLs were developed, how sensitivity analysis was performed and how the sensitivity results are being used.
"* Justify sensitive parameters listed in Table 4, i.e.:
indoor time fraction (M, metabolic, B, behavior) = 0.5 external gamma shielding factor (P, physical)= 0.7 contaminated fraction of plant food (B, P) =1 contaminated fraction of meat (B, P) = 1 depth of roots (P) = 0.9 meters livestock fodder intake for meat (P) = 68 kg/day contaminated zone thickness (P) = 1 meter
2 - RAI2 Q4 Issues (cont.)
"* Clarify use of national data as central tendency.
OK if non-sensitive parameter If sensitive parameter need to justify
"* Need to provide greater detail for sensitivity analysis.
Cutoff criteria Sensitivity analysis performed on each radionuclide Expand Table 4 to include sensitive parameters that are not listed:
"* Plant, meat, and milk transfer factors
"* Saturated zone hydraulic conductivity
"* Depth of soil mixing
"* Wind velocity
"* Need to provide RESRAD output reports on sensitivity analysis.
"* Explain why contamination in the shallow and deep systems are independent and mutually exclusive.
2 - RAI2 Q4 Issues (cont.)
"* Discuss rational for using lowest Kd value.
"* Review hydraulic slope range values.
"* Provide statistical parameter for the sensitivity analysis, i.e. min/max values only useful for the uniform, normal-b and lognormal-b distributions.
"* Justify the issue: 75% of the livestock and irrigation is derived from on site sources. Why is this a conservative and acceptable assumption?
"* Explain why contaminated fraction of food and meat parameters are sensitive and include in probabilistic analysis.
"* Use of DandD defaults for behavior parameters - Inputs recommended by NRC from a February 2001 meeting w/SNEC.
"* Justify and bound the use of the 10,000 m2 contaminated zone area. Is this consistent with assumptions made in developing survey units.
NRC needs to clarify.
3 - RAI2 Q5 Issues
- Indicate why Kd is the only factor considered in determining DCGL values applied to site media.
- Show why the lowest Kd value provides a conservative assessment of dose. (Also asked for in RAI2 Q4.)
4 - RAi2 Q6 Issue Clarify the term "or an equivalent form."
- SNEC plans to use MARSSIM Equation 4-4 to calculate gross DCGLs. Equation is in the SNEC LTP, section 5.2.3.2.4.
Equivalent denotes using Eq. 4.4 in its exact form or extending the series to include multiple fractions and radionuclide types.
- Explain when and how gross activity DCGL values will be provided.
5 - RAi2 Q8 Issues
"* Need to provide electronic copy of subsurface dose model.
Explain how subsurface DCGLs were derived.
"* Discuss why SNEC chose non-dispersion (ND) vs mass balance (MB) when withdrawing contaminants from a hypothetical well.
"* Explain use of Kd values for the following:
Justify default Kd's for Ac, Pa, Po, Ra, Th Justify use of upper-end Kd of 5 for C and H
"* Provide statistical parameters for sensitivity analysis. Use of min/max values only useful for uniform, normal-b, and lognormal-b distributions.
Determine basis for dilution factor of 1/5 for contaminants in overburden material assumed to be brought to the surface.
Justify rational for deriving irrigation water from diluted shallow zone vs undiluted deep zone.
7 - NRC Site Visit Comments SNEC has decided to completely remove CV concrete.
Requires revision to LTP Sections 2,3,4 & 5.
Requires revision of survey units described in LTP Table 5-2.
New survey units will need to be created for exposed steel surfaces.
To avoid CV wall collapse steel reinforcement rings will be installed.
Need to evaluate ring interferences for characterization and FSS surficial measurements.
Provide to NRC figures describing new survey units and tables indicating the nature and extent of contamination. Also, describe new survey/sampling techniques including automated advanced technology devices used for characterization and FSS surveys.
Provide to NRC DQOs for such devices.
For CV dome removal describe the radiological controls to avoid recontamination of lower CV structure. Also, provide protocols to ensure clean fill is used.
8 - Review of Phase 1,2 & 3 Characterization Data
"* NRC concerns on minimal or no TRU/HTD radionuclide data.
"* Clarify sample/measurement data needs.
Use of confidence levels Analytical techniques for identifying TRUs need to be stated.
Explain why majority of data is specific to Cs-137.
Provide survey unit figures for the SSGS and indicate the location of samples of significant activity.
Provide rational for classifying Intake Tunnel as a Class 3 area.
"* Reflect the reclassification of weir outfall from class 1 to class 2 in LTP Table 5-2. Survey unit size is defined as 25 M2.
9 - Key Additional Issues from Current LTP
- Figures need to indicate specific survey units with appropriate sampling and measurement locations depicted and correlated to classification tables.
Discuss use of Figure 5-1 and treatment of survey areas containing multiple survey units.
Discuss content of Final Survey Report adequacy as per LTP Section 5.7.2.
Status of CV Tunnel classification. This structure is to be removed and therefore does not need to be classified.