ML20148F436
| ML20148F436 | |
| Person / Time | |
|---|---|
| Site: | 07000754 |
| Issue date: | 09/28/1978 |
| From: | Cunningham G GENERAL ELECTRIC CO. |
| To: | Kratzke R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 7811090010 | |
| Download: ML20148F436 (6) | |
Text
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G EN ER AL N ELECTBJ C
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k gCtW ENGINEERING l
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g6 TC7N, b LIFORNIA 94568 h
DIVISION GENERAL ELECT AIC COMPANY, P.O. DOX 460, I
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September 28, 1978
"(t;. g u.S[
,g Fuel Reprocessing and Recycle Branch D
Office of Nuclear Material Safety & Safeguards U.S. Nuclear Regulatory Commission Imc m~" ~ " m M'&
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Washington, D.
C., 20555 Attention:
Mr. R. T. Kratzke
Reference:
1 License SNM-960, Docket 70-754 l
2 Application for Renewal of License SNM-960, 8/20/71 l
3 Letter, R. W. Starostecki to G. E. Cunningham, 11/21/77 4
Proposed Draft License Conditions to SNM-960, 9/5/78
Dear Mr. Kratzke:
Enclosed are revised pages to the proposed Appendix A to License SNM-960
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and to Section 5.0 of the Safety Demonstration.
These changes are in response i
to the draf t license conditions proposed by R. L. Stevenson.
In addition, Mr. Stevenson requested information concerning the most recent
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criticality safety analysis for the AFL and information concerning the use
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of SNM receipts from D.O.E. contractors.
With respect to the criticality safety analysis, although the analysis has been completed, the formal docu-
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mentation is still in progress. Accordingly, VNC plans to submit the requested l
summary of the analysis by October 20, 1978.
SNM receipts from D.0.E. contractors are not released for process until confir-mation of assay and not until the magnitude of the shipper-receiver dif ference (if any) is known.
If the difierence is not significant from a criticality safety point of view, the material may be introduced into tne process prior to resolution of the difference.
To date there have been no_ shipper-receiver differences between D.O.E. contractors and the AFL which could be considered to pose a criticality safety hazard.
Should such a difference occur, the material v:3uld'not be introduced into the process until the difference was resolved, and the material would be stored and handled using the most conser-vative (from a criticality safety point of view) assay numbers.
i Sincerely, kl*
G. E. Cunningham Sr. Licensing Engineer vcc M] ** 3 lucl.
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.in addition to reflection of the array, interspersed water moderation within the array may l
also reduce the capacity (the number of accumulations required for a critical array) for i
high enriched uranium arrays.
It has been found* that the addition of optimum l
interspersed moderation reduces the capacity of a reflected array of unmoderated metai i
j units by a factor of about 2.5. This factor may be reduced as the units approach optimum moderation and no reduction factor is necessary for optimum moderated units.
This method, however, may not be applied to units enriched to less than $96 subject to y
interspersed moderation.
in general then, the density analog method utilizes the following equation in the case of l
reflected arrays of unmoderated (metal) units with optimum interspersed moderation:
M
/ Y 6
i cs uc c
2.5 R M
(Yuj u
f in the case of reflected arrays of optimum moderated units, the equation is:
1 M
/V I
1 cs uc c
R M
V j
u u/
4 h
l 1
1
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i l
- Criticality Safety Evaluation of Packages for the Transport of Fissile Material, D. R. Smith, Albuquerque,1965; and Experimental and Calculated System Crit (cality, J. T. Thomas, Stockholm.
License No.
SN M-960 Docket No.70-754 Sect. No. 5.4.4 (cont'd)
Page 5-9 Date 9-27--78 Amends Sect.(s)
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5.7 CRITICALITY CONTROL INSPECTIONS 5.7.1 The radiation safety component shall be responsible for inspecting each criticality area on a continuous basis to assure compliance with criticality control procedures.
Items to be inspected shall include, but not be limited to, the posting of criticality 1
control limits, the labeling of SNM containers with information needs for criticality control purposes, the movement of SNM,' and general criticality safety work practices.
5.7.2 A program of inspection shall be performed by criticality specialists of the criticality safety component to determine that actual operations conform to the physical situations on which the calculations of criticality limits have been based.
Inspection reports shall be furnished to area managers.
Where situations are identified which require corrective action, such reports shall so indicate.
Corrective or follow-up action shall be taken in accordance with VNC Site Safety Standards and/or site nuclear safety procedures.
Operations which handle routinely in process more than one safe batch (as def!ned 7
in Section 3.10) of fissile material shall be inspected on a quarterly basis. All operations shall be inspected on an annual basis.
5.8 TRAINING PROGRAM Area managers shall assure that new employees receive instruction in criticality safety and plant operating and emergency procedures prior to their working with special nuclear materials.
A criticality control training program, approved by the criticality safety component shall be maintained to emphasize the need for following criticality control procedures and to aid personnel in understanding the various parameters which are essential to the maintenance of subcritical conditions. The program may be conducted by
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the criticality safety component or some other portion of the nuclear safety component and may be combined with radiation safety training. A written test shall be completed by each employee taking the course. The test shall be evaluated and the results forwarded to the appropriate area manager.
5.9 MONITOR ALARM SYSTEM 5.9.1 No transfers of fissile materials between criticality limit areas or between vessels within a criticality limit area shall be permitted in criticality areas monitored by systems which would not function following loss of primary electrical power.
Transfers may resume following restoration of power and verification of the monitoring system's operability.
5.9.2 Exemption from the monitor alarm requirement of Section 70.24(a)(2) of 10CFR70 is granted for the fuel storage pool in Building 304 and the Radioactive Products and Services Laboratory (RP&S) pool and hot cells. At the high level solid waste storage facility and the storage pit in the RP&S pool area, for the purpose of compliance with 70.24(aX2) of 10CFR70, the source of a possible accidental condition of criticality may be considered as the accessible surface of the earth or concrete shielding.
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5.9.3 Specific exemption from the prescribed preset alarm points (5 to 20 mrem /h) is granted for those monitoring devices where the routine movenient of by-product materials could result in gamma fields at the monitoring devices in excess of those that would result in a dose rate of 20 mR/h. Further, the alarm setting for these monitoring devices under the above conditions shall not exceed 500 mrem /h.
. License No.
SNM-960 Docket No.70-754 Sect. No.
5.9.3 Page A-5-2 APPENDlX A Date September 27.1978 Amends Sect.(s)
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- 6. CRITICALITY CONTROL CONDITIONS-TECHNICAL AND ANALYTICAL REQUIREMENTS 6.1 GENERAL REQUIREMENTS f
Criticality controls shall be based on the normal environmental conditions in the criticality area and also on all credible abnormal conditions that could affect the criticality safety in that area. These factors shall include, but not necessarily be limited to, moderation, reflection, neutronic interaction, fissile material accumulation size, physical form, chemical and isotopic composition, nuclear poisons, density, concentration, reliability of equipment, type of operation, and training and supervision of operating personnel.
In evaluating the subcriticality of individual accumulations, process configurations, or arrays of fissile material, the two-contingency criterion shall be applied. That is, two unlikely, independent, and concurrent accidents or changes in process conditions must occur before criticality is credible.
6.2 CALCULATIVE METHODS Criticality analyses shall utilize calculative methods that produce results which, when compared with critical experimental data for similar systems, correspond with the level of agreement with experimental data described in Section 5 of the application. For purposes of this license condition 6.2, the methods of Section 5 of the application may be refined to produce closer agreement with critical data. New calculative methods and refinements of previously used methods shall be subject to independent review and verification by persons with demonstrated competence in neutron physics computations before use, f
6.3 NORMALLY SUBCRITICAL VALUES-INDIVIDUAL ACCUMULATIONS Normally subcritical values of nuclear parameters for individual accumulations under normal operating conditions shall be:
1.
For accumulations limited by mass, the normally subcritical mass shall not exceed 75% of the critical mass.
2.
For accumulations limited by volume, the normally subcritical volume shall not exceed 76% of the critical volume.
3.
For accumulations limited by dimension, the normally subcritical cylinder diameter or slab thickness shall not exceed 90% or SS%, respectively of the critical dimension where U-235 is the fissile constituent, nor 85% in all other cases.
4.
For accumulations limited by concentration, the normally subcritical concentration shall be less than that concentration which is equivalent to the following atomic ratios of hydrogen to fissile material: H/U-235, 5200; H/U-233, 7600; and H/Pu (fissile),7600.
5.
For accumulations limited by reactivity, the normally subcritical reactivity shall not exceed 90% of critical.
I 6.
Not more than 45% of the critical mass shall be contained in 'any accumulation in a criticality limit area in whDb double batching is credible.
License No.
SNM460 Docket No.70-754 Sect. No.
6.3 Page A-6-1 APPENDIX A Date September 27.1978 Amends Sect.(s) 1
,4 6.4 NORMALLY SUBCRITICAL VALUES-INTERACTING ACCUMULATIONS Normally subcritical (as defined in Section 3.6) numbers of interacting accumulations i
shall be:
l 1.
Not more than 50% of the critical number of accumulations whenever the l
1 critical number has been determined by experiment; or 2.
Not more than 77% of the critical number of accumulations in any array calculated by the density analog method (Ref: ARH-600); or 3.
The number of accumulations determined by the solid angle method as described in TID-7016, Rev. 2, Paragraphs 4.29 through 4.34. For plutonium or uranium systems of more than five percent enrichment, the method may be applied only to accumulations that are well moderated (e.g., aqueous solutions)
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at the point of maximum reactivity, and array reflection must be no more
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effective than a thick water reflector spaced at distances from the accumulations comparable to the spacing between accumulations.
6.5 INTEGRITY OF STRUCTURES 6.5.1 Whenever criticality control is directly dependent on the integrity of a structure
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used to retain a special nuclear material storage array, the structure will be j
designed with an adequate strength factor to assure against failure under 5
foreseeable loads or accident conditions. Materials of construction will be selected to resist fire and the degree to which any corrosive environment might affect nuclear safety will be considered and corrosion resistant materials or coatings applied as necessary. The design shall be reviewed by a qualified engineer.
6.5.2 Whenever criticality control is directly dependent on the integrity of a neutron isolating structure, the structure will be designed to assure against loss of integrity through foreseeable accident conditions; such as fire, impact, melting, corrosion or leakage of materials. The design shall be reviewed by a qualified engineer.
6.6 OPTIMUM CONDITIONS OF MODERATION AND REFLECTION Unless moderation or reflection is controlled by physical and administrative means in accordance with Sections 6.7 or 6.8 below, calculations of criticality control limits shall be made assuming that optimum light water moderation and full reflection by light water exist, consistent with the form of the fissile material and its container. When mass limitation is to be employed for criticality control of an accumulation of fissile material, optimum moderation is that degree of moderation which minimizes the mass of material that is required to achieve criticality. When a geometric limitation is to.be employed for criticality control of an accumulation of fissile material, optimum moderation is that degree of moderation which maximizes the material buckling.
License No.
SN M-960 Docket No.70-754 Sect. No.
6.6 Page A-6-2 APPENDIX A Date September 27,1978 Amende Sect.(s)
g 6.10 NUCLEAR ISOLATION r/
Two accumulations or arrays of accumulations may be considered as being nuclearly isolated from each other only if an edge-to-edge separation exists which is not less than one of the following or its nuclear equivalent:
1.
Eight inches of water.
The larger of '12 feet or the greatest distance across an orthographic 2.
projection of either accumulation or array on a plane perpendicular to a line joining their centers, j
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i a
License No.
SNM-960 Docket No.
70 -754 Sect. No.
6.10 Page A-6-4 APPENDIX A Date September 27,1978 Amends Sect.(s)
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