ML20023B148
| ML20023B148 | |
| Person / Time | |
|---|---|
| Issue date: | 12/02/1982 |
| From: | Ornstein P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Knapp M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-1 3407.26-PMO-82, NUDOCS 8212230191 | |
| Download: ML20023B148 (5) | |
Text
.
Distribution:
3407.26/PM0/82/11/22/0 DEC 0 21982 jg f
/
NMSS r/f
{-j],,
/
JBMartin REBrowning PP D MJBell WMHL:
3407.26 L ddQ PM0rnstein & r/f (r.aturn to mf, 623-ss HJMiller MEMORANDUM FOR:
Malcolm R. Knapp J0Buntir.g SMCoplan High-Level Waste Licensing RLJohnson Management Branch RJWright Division of Waste Management FRCook MWPendleton FROM:
Peter M. Ornstein JStarmer High-Level Waste Licensing PDR Management Branch Division of Waste Management
SUBJECT:
ANS MEETING: November 17, 1982 MEETING
SUMMARY
The ANS meetings on HLW performance assessment provided a forum for discussion of each of the DOE sites.
However, the meetings had very limited attendance; the great majority of the attendees were NRC and DOE staff and contractors.
Very little new information was unveiled in the papers presented and the presentations discussed only the positive aspects of site suitability.
Highlights of the information presented include:
- Site selection for salt will be made in May 1983.
- The Vacherie Dome was not recommended for site selection on the basis of thermomechanical modeling.
- The WAPPA (Waste Package Performance Assessment) code (see attached presentation by Pearson) may be used for all three media.
- Vertical conductivity tests are being planned for BWIP.
- NTS groundwater travel times along the water table between Yucca Mountain and well J-13 (6.4 Km distance) are calculated to be 1,200 years.
OFC :
NAME :
DATE :82/11/22 8212230191 821202 PDR WASTE WM-1 PDR
3407.26/PM0/82/11/22/0 DEC 0 21982 Most of the underlying assumptions and specific details behind the calculations and figures presented were not discussed.
Technical evaluation of the presentations could not be made without a much greater level of information.
A short synopsis of each of the presentations follows.
PRESENTATION SUMMARIES Repository Safety - The Salient Facts, presented by W. M. Hewitt (ONWI).
Dr. Hewitt discussed the positive aspects of locating a repository in salt.
His four major points were:
1)
Salt is capable of isolating waste from circulating groundwater.
The groundwater attack on the weste package will be minimal and will be controlled by diffusion forces.
2)
Long travel times.
Flow velocities in the lower aquifers of the Paradox and Permian (Palo Duro) Basins are 1.0 to 10.0 cm/yr.
3)
Uptake to humans is minimized.
The probability of release due to human intrusion exceeds that of release due to natural processes.
4)
Ammount of waste at risk is minimized.
Salt creep will close off and seal boreholes.
In response to a question from the audience, Hewitt said that site selection for salt will be made in May 1983.
Thermomechanical Modeling and the Selection of a Salt Repository Site, presented by H. Y. Tammermagi (RE/ SPEC).
Dr. Tammenagi proposed a ranking system for evaluating the thermomechanical performance of the four salt sites being considered (Paradox Basin, Permian Basin, Vacherie Dome, and Richton Dome).
Ranking was performed by scoring specific aspects of each of the sites.
Scoring was done for each aspect (or " basis for comparison") according to the formula:
score = (C-BFC)(WF/C),
OFC :
NAME :
2/$22 l
DATE 1
r e
DEC 0 21982 3407.26/PM0/82/11/22/0 where BFC is the basis for comparison (e.g., maximum temperature for salt), C is a constraint (e.g., maximum temperature should not exceed 200*C), and WF is a weighting factor (i.e., on a scale of 0-100).
Determination of C and WF appear to be judgemental.
As per this ranking, the Permian Basin came out slightly ahead of the Paradox Basin and the Richton Dome.
Vacherie Dome came out a distant fourth and was recommended not to be pursued.
Post-Closure Performance Assessment Methodology for the Office of Nuclear Waste Isolation, presented by R. E. Wilems (INTERA).
Dr. Wilems discussed the computer codes which will be used for performance assessment of the salt site (s).
These include:
1)
Flow:
NETFLO, SWENT 2)
Transport: GETOUT, MMT, SWENT 3)
Biosphere: PABLM The codes have been reformatted whereby output from one code can be used directly as input to another code.
Other codes mentioned for possible use included nearly every code in the ONI inventory.
WAPPA: An Integrated Waste Package Performance Assessment Code, presented by J. Pearson (INTERA).
The primary purpose of the WAPPA code is to provide source terms for repository models.
However, WAPPA can also be used to analyze the waste package itself.
The model consists of six submodels (i.e., Radiation, Thermal, Mechanical, Corrosion, Leaching, and Transport) which are sequentially solved in the order listed above at each time step.
The model will be used at the salt site (s) and is being made available to RHO and SNL for possible use at BWIP and NTS.
Application of Performance Assessment Models to Evaluate Uncertainty in Site Characterization, presented by R. W. Andrews (INTERA).
Dr. Andrews gave a technical discussion on the mathematics and application of the Adjoint Method in evaluating data uncertainties.
The i
technique, which enables evaluation of parameter sensativities, has been j
applied to the ONWI salt sites (not discussed).
The theory is still l
being developed.
OFC :
l NAME :
l l
DATE :82/11/22 l
3407.26/PM0/82/11/22/0 DEC 0 21982 Satisfying Performance Assessment Data Needs, presented by unknown.
This talN outlined data needs and plans for the BWIP site.
The primary du+.a needs are vertical hydraulic conductivities.
To obtain this data, large scale well tests will be performed in wells DC4 and 5, and DC7 and 8.
Cluster testing-is planned in wells DC16a, b and c.
Waste Package Performance Assessment:
The Importance of Very Near-Fis1d Physicochemical Environment, presented by G. X. Jacobs (RHO).
This discussion focused on the near-field environment as a barrier to radionuclide migration.
Radionuclide sorption onto basalt may, in part, be irreversible, thereby tying up any releases.
Thermal stress will be the primary groundwater diving force and will effect a very small fluid velocity.
Eh conditions in the basalt aquifers are very low indicating low radionuclide solubility.
Performance Assessment in the Nevada Nuclear Waste Storage Investigations, presented by L. Tyler (Sandia).
Dr. Tyler discussed transport model development for NTS and a preliminary modeling study for radionuclide transport between Yucca Mountain and well J-13 (approx. 6.4 km distance).
SAGUARO (documentation not yet available) will be used to model nonisothermal unsaturated flow.
It will consider vaporization /
condensation processes and will be coupled to the FEMWASTE transport code.
TRACR3D (documentation not yet available) will be used to model flow and transport through saturated fractured media.
The modeling study Tyler discussed assumed vertical flow from the Topopah Spring unit to the water table, and then horizontal along a " transmissive zone" directly to well J-13.
Travel time for an unattenuated nuclide was 21,000 years vertically to the water table and 1,200 years horizontally to well J-13.
With Kd = 1 (arbitrarily chosen to exemplify the effects of retardation), travel times were 162,200 years vertically and 12,700 years horizontally.
System Study and Performance Constraints for Repository Horizon Selection at the Nevada Test Site, presented by J. K. Johnstone (Sandia).
Dr. Johnstone presented a ranking of the four geologic units being considered at NTS for repository siting.
The ranking was performed on 0FC :
NAME :
DATE :82/11/22
DEC 0 21982 3407.26/PM0/82/11/22/0 the basis of waste isolation ability, thermal loading, and economics.
Travel times for each unit were calculated in the manner presented by Tyler (see description of Tyler presentation).
The ranking from most to least favorable, as well as unattenuated vertical travel times to the water table, is as follows:
Topopah Spring (21,000 yrs.), Calcio Hills (11,100 yrs.), Bullfrog (95 yrs.), Tram (303 yrs.).
Although the Topopah Spring horizon is most favorable, none of the other horizons have been eliminated from contention for possible siting.
Consequence of Basaltic Volcanism Throuoh a High-Level Waste Respository, presented by R. L. Hunter.
Dr. Hunte attempted to show that given a worst case scenario for volcanism at NTS, radionuclide release will be minimal.
Calculations were performed on a hypothetical 1.5 Km diameter basaltic volcano emerging through the center of the repository block.
At repository depths, thin dikes feeding the basaltic core would intercept approximately one waste canister.
Utilizing other assumptions, Dr.
Hunter calculated that worst case exposure levels to humans living on and around the Yucca Mountain site would be not much greater than background levels.
ORIGI MLsimcany l
Peter M. Ornstein High-Level Waste Licensing Management Branch Division of Waste Management l
1 0FC
_j,__;____________l____________'____________ ____________ ___________ '___________
_____: WMH c.
NAME;P,_tgstgigilyc___________;____________;____________'____________'____________;_______
DATE : 32/ LL/82
-~
-