ML20237L218
| ML20237L218 | |
| Person / Time | |
|---|---|
| Issue date: | 08/29/1985 |
| From: | Higginbotham L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Mittel R Public Service Enterprise Group |
| Shared Package | |
| ML20237L079 | List: |
| References | |
| REF-WM-91 NUDOCS 8709080291 | |
| Download: ML20237L218 (2) | |
Text
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,UOt.E AR REGULATOR Y COMMISSION
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Mr. R. L. Mittel
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and Gas Company N ALM /a~Ng P.O. Box 570 T*
fiewark, f4J 07101 cws nu p
Dear Mr. Mittel:
j This letter is in response to your correspondence dated July 3,1985, which presented your views concerning stability requirements for non-brittle waste' forms or, more specifically, for asphalt.
We are currently considering means of addressing the behavior of bitumen under the compressive loads of burial which maintain the intent.of the stability requirements presented in 10 CFR 1
561.56. We appreciate your input on this matter.
In your letter, you have raised two objections to the possibility of requiring administrative controls for the backfilling of asphalt waste forms.
j Restating your objections, they were; first, that voids created by the viscoelastic creep of the waste form will contribute nothing to trench subsidence and secondly, since 10 CFR Part 61 already requires backfilling of the void spaces it is 4
l unnecessary to impose sdcitional requirements on asphalt waste foms.
In response to the first objection, we submit that while the creep of an asphalt waste form into adjacent void spaces, does not increase the total void volume within a trench, it may allow the redistribution of the voids so as to permit wastes at higher elevations to move. downward.
It is this scenario which may lead to eventual trench subsidence.
This concern will intensify as more asphalt systems come on-line and the volume of asphalt waste forms become a significant percentage of'the trench volume.
Regarding your second objection, please consider the stability requirements of Section 61.56(b) which state that " stability is intended to ensure that the waste does not structurally degrade and affect overall stability of the site through slumping, collapse, or other failure of the disposal unit..."
further states that a " structurally stable waste fom will generally maintain It its physical dimensions and its fom, under the expected disposal conditions..."
The waste foms which are currently being buried at the disposal sites (brittle waste forms) meet these requirements and in so doing they meet the the release of radioactivity, 661.41 and the stability of the 961.44.
Since these wasta forms meet the intent of the Performance Objectives it is unnecessarFpAorins+st that44ictingent backfilling procedures be exercised 9
to completely elpndne e ge yoi,d7 pace However, since asphalt waste foms s.
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may not maintain their physical dimensions they raise doubt and uncertainties as to whether they can meet the intent.of the Performance Objectives with the current backfilling practices (as mentioned in the preceding paragraph).
l In order to address the uncertainties re'garding asphalt's viability..we are-proposing the following' options for those waste forms which deform in.a non-brittle manner.
1 1.
A creep test similar to ASTM 0-621 in which the constant test load I
simulates the burial load.
Failure may.be defined, for example, as greater than 10 percent deformation extrapolated to 300 years.
2.
Alternatively, the vendor could show that a -plan for administrative controls on backfilling.has been established with the site operator before their waste forms are emplaced at the disposal site. -The-3 controls will insure that the voids between'the waste forms are eliminated, thereby providing the structural stability required by 10 CFR Part 61, assuming that the waste form is not subject to degradation by other-burial site mechanisms.
3.
Any other approach which demonstrates consistency with the Performance Objectives will be considered.
We hope these coments help to clarify our position on this issue.
Shoulo you have any further questions or suggestions, please contact Mr. Timothy C. Joanson (301) 427-4088 or Mr. Thomas Jungling (301) 427-4540.
Sincerely, 1
87 Hi botham Chlef Low-level aste and Uranium Recovery Projects Branch 1
Division of Waste Management Office of Nuclear Material Safety and Safeguards l
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Ref: SA/KftS I
firs.14ancy P. Kirner, Supervisor Waste llanagement Unit Department of Social and Health Services Mail S' top LF#13 01ympla, Washington 9S504 l
Dear Mrs. Kirner:
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The NRC staff has received'a request dated November 5,1985 (enclosed) from Associated Technologies Incorporated to permit their client utilities to ship bitumen solidified waste to the low-level radioactive waste disposal facilities while a topical report is under review.
~ We recommend that. interim acceptance be granted with the. provision that I
Class B and C waste forms receive' sufficient backfill around the drums
, -- of bitumen; solidified; waste;tolainimize voids prior to placing j
additional' waste above such wastes. A bitumen waste fom without a j
container will flow if adjacent voids are present. and improved J
backfilling procedures would be necessary to minimize the voids and
. insure trench stability. ATI intends to begin solidification operations in January 1986.r..
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l We have also enclosed additional NRC correspondence on asphalt and NUREG/CR 3829' which discusses the flow problem.
P1 case infom us of your decision. If you have any questions, please contact Mrs. Schneider at 301-492;9893.
~
Sincerely, original signed by I
J. O.Lebenau Donald A. Nussbaumer Assistant Director for State Agreements Program Office of State Programs
Enclosure:
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