ML20196A402
| ML20196A402 | |
| Person / Time | |
|---|---|
| Site: | 07000754 |
| Issue date: | 11/20/1998 |
| From: | Murray B GENERAL ELECTRIC CO. |
| To: | Gaskin C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| TAC-L31098, NUDOCS 9811270138 | |
| Download: ML20196A402 (13) | |
Text
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GE Nuclear Energy Geew newc cmim Vshwo: Lchw Cwer November 20,1998
" " 38" # """ *
- C Charles E. Gaskin, Project Manager Licensing Section 1 Licensing Branch Division of Fuel Cycle Safety and Safeguards, NMSS Washington, D.C. 20555
Subject:
Reply to Request for Additional Information for Changes to Appendices A & B (TAC No. L31098)
References:
- 1) Letter and Enclosure from Charles E. Gaskin to Ben M. Murray, dated October 22,1998.
- 2) Letter from B M. Murray to Michael F. Weber dated July 9,1998.
- 3) License SNM-960, Docket 70-754
Dear Mr. Gaskin:
The following discussion and enclosures address the request (Ref.1) for additional information for changes to Appendices A and B to our material license, SNM-960. The itemized requests are presented followed by our reply:
- 1. Page A-5-4, Appendix A, Section 5.9.2: Correct the references to 10CFR70.24. Didthe licensee intend to change its commitment regarding the criticality accident alarm systemfor 10CFR70.24from 70.24(a)(2) to 70.24(a)(1) throughout the license? Ifso, correct thefirst referencefrom 70.24(a) to 70.24(a)(1).
RepIv: The intent was to change our commitment regarding the criticality accident alarm system for 10CFR70.24 from 70.24(a)(2) to 70.24(a)(1) throughout the license. A revised page A-5-4 is enclosed.
)
l 2.
Page A-5-4, Appendix A, Section 5.9.3 (new) (5.9.4 (old)]: Correct the reference to a "subcritical area" definitionfrom Section 3.15 to Section 3.17.
Reply: The reference was corrected in the enclosed page A-5-4.
&o l
3.
Page 3-5, Appendix B, Section 3.8: Correct the reference to a "subtritical area" definition from Section 3.16 to Section 3.17.
Reply: The reference was corrected in the enclosed page 3-5.
9811270139 981120 D
PDR ADOCK 07000754 C
Charles E. Gaskin November 20,1998 4.
Page 6-9, Appendix B, Figure 6.2: Add the locations ofthe three detectors around the Radioactive Materials Laboratory to Figure 6.2 (as Mentioned in Page 7-6, Section 7.3.10).
Reply: The criticality detector locations were added to Figure 6.2 in the enclosed page 6-9.
- 5. Section 10.1.1 presents the licensee 's proposedgaseous stack effluent action levelsfor the site. Some ofthe action levels listed are larger than the NRC 's 10 CFR Part 20 release
\\
limits. NRC assumes that these action levels are higher than Part 20 limits because the j
levels are measured at the stack and there would be dilution ofthese emissions prior to reaching the sitefence line, which is the boundaryfor the licensee to meet Part 20 limits.
However, there is not enough information providedfbr the NRC to determine ifthese action levels are sufficient to prevent gaseous dischargesfrom crossing the site boundary at levels greater than Part 20 limits. Provide thefollowing information tojustify the request to change gaseous stack action levelsfor the site:
a) a detailed list ofthe specific isotopes (e.g., U-235, Pu-241) which are discharged from the site; b) a detailedlist ofthe specific isotopes (e.g., U-235 Pu-241) which are measured under each ofthe Gross Alpha, Gross Beta, andNoble Gasesparameters; c) the specific information used to determine that the requested stack action levels will assure that the site will meet Part 20 limits (e.g., stack height, distance tofence line, wind rose information, X/Q calculations, and dilutionfactors-enough information should be provided so that the NRC can perform confirmatory calcidations); and, d) a writtenjustificationfbr the use ofthe new action levels and how these action levels will assure that Part 20 limits and, specifically, the 10 mrem /yr dose constraint contained in 10 CFR Part 20.1301(d) will be met.
j Reply: The NRC's assumption concerning the dilution of releases from the points-of-release (stacks) to the site fence is correct. The determination of the release limits for the VNC cffluent stacks is contained in Attachment A to Vallecitos Safety Standard 7.2 (VSS 7.2," Radioactive Effluent Control"). This evaluation is enclosed as Enclosure 1.
l Specific replies to the sub-items follow:
i a) The airborne effluent releases from VNC stacks are normally maintained at levels close to or below the detection limits of the sampling and counting systems. Any released radioactive inaterials are not identified beyond the four general isotope group categories of gross beta, gross alpha, I-131, and noble gases. The limits for each group are based on the realistic, most l
restrictive isotope of a particular group. The inventory ofisotopes which are present in the
(
facilities at VNC are primarily composed of the typical isotopes found in irradiated reactor fuel and hardware. Any unusual isotopes, such as Pu-238, Thorium, Np-237, etc., are I
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Charles E. Gaskin November 20,1998 possessed in small quantities and stored in sealed containers. The radioactive airborne effluents are filtered by at least one bank of HEPA filters. The effluents from the hot cell facilities, where the largest inventory of releasable radionuclides are possessed and handled, are passed through double banks of11 EPA filtration as a minimum, and in some cases triple filtration.
b) As stated in a) above, the actual composition of any released particulate isotopes is not determined. In addition to the conservatism of using release limits based on restrictive isotopes, the identification of actual releases is impractical due to the low or non-existence of actual inventoried isotopes on the sample medium. The measurable releases consist ofI-131 and other fission gases. The gaseous releases from Building 105 result from the fissioning of
" tramp" uranium in the aluminum matrix plate fuel and air activation in the NTR reactor (License R-33). The Xe-133 gas releases from Building 102 occur during the purging of vacuum pumps in the xenon packaging facility.
c) The specific information used to determine that the requested stack action levels will assure that the site will meet Part 20 limits are presented below. The calculation of the maximum annual average dilution-dispersion factor (x/Q) used five years worth of useable hourly meteorological measurements. The hourly wind velocity and stability values were extracted from charts and hard logged for computer processing. The wind data in conjunction with the boundary distances for each of 16 equal radial sectors were used to detemiine the average dilution-dispersion values. From these evaluations, the maximum annual average X Q values
/
were determined from the Building 102A stack, which has the highest potential for a major release (due to the building inventory of radioactive material) and the shortest distance to the site boundary fence. A table of the wind frequency to the southern sector, which is the sector with the highest annual average X Q, is included as Enclosure 2.
/
Stack height................
.. Assume ground level releases Distance to fence line (from Bldg.102A stack), m..... 386 Annual average dilution-dispersion factor, sec/ml..... 8.25E-11 d) The written justification for the use of the new action levels is included in Enclosure 1, the Attachment A to Vallecitos Safety Standard 7.2. The derivation of action levels in Enclosure 1 uses the basic requirement to maintain boundary doses below 10 mrem /yr.
Another typographical error was discovered on page A-8-1 of Appendix A to SNM-960. The referenced paragraph in paragraph 8.1.1.6 should be 8.1.1.5, instead of 8.1.5, in parentheses. A revised page A-8-1 is enclosed.
t Charles E. Gaskin November 20,1998 1
If more information is required, please feel free to contact me at (925) 862-4455.
Very truly yours, l
"mb->
B. M. Murray
(
Senior Licensing Engineer Regulatory Compliance
/ Enclosures l
L i
1
5.9. CRITICALITY MONITORING 5.9.1 No transfers of fissile materials between criticality limit areas shall be permitted in criticality areas required to have a monitor alarm system unless the system is operable.
Transfers may resume following repair and verification of the monitoring system's operability.
5.9.2. Exemption from the monittt alarm requirement of Section 70.24(a)(1) of 10CFR70 is l granted for the Remote Hand.:ng Operation (RHO) pool and hot cells. At the high-level solid waste storage facility ano the storage pit in the RHO pool area, for the purpose of j
compliance with 70.24(a)(1) of 11CFR70, the source of a possible accidental condition of criticality may be considered as th. ccessible surface of the earth or concrete shielding.
1
.5.9.3 Exemption from the requirements of Section 70.24 of 10CFR70 is granted for each area in which there is not more than one shipment of packages containing special nuclear materials licensed pursuant to 10 CFR Part 71 for transport outside the confines of the Vallecitos Nuclear Center (packages in any shipment which depend on special arrangement for nuclear safety shall be retained in that same arrangement during such storage); or one safe batch of finished reactor fuel rods of assemblies, providing no 1
activities could cause rearrangement of fuel-bearing portions into more reactive configurations; or which meets the requirements of a suberitical area as defined in Section 3.17 of this Appendix.
I License No. SNM-960 Docket No.70-754 Sect. No.
- 5. 0 Page A-5-4 Appendix A Date 11/19/98 Amends Sect.(s) 5. 9. 2. 5. 9. 3 t
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l 8.0 RADIATION CONTROL CONDITIONS -
TECHNICAL AND OPERATING REQUIREMENTS 8.1 AIR CONTAMINATION CONTROL l
The following design criteria for ventilation systems shall be used to provide air 8.1.1 l
contamination control.
8.1.1.1 Airflow shall be from areas oflesser contamination to areas of higher contamination.
Potential accident conditions shall be considered.
8.1.1.2 Duct flow velocities and design shall be such to minimize possible accumulation of contamination.
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l 8.1.1.3 Air shall be sampled continuously in normally occupied areas in which dispersible i
SNM is handled. Samples are analyzed for gross alpha and gross beta-gamma.
8.1.1.4 Potential airbome radioactivity-producing operations shall utilize close-capture l
ventilation devices, e.g., hoods and high-velocity local exhaust when compatible with ALARA.
8.1.1.5 All ventilation exhaust systems for facilities that routinely handle dispersible SNM in l.
quantities in excess of the limits specified in Appendix C of 10CFR20 shall be sampled continuously as proof of filter performance. All HEPA filters for such facilities will be j
fire resistant.
8.1.1.6 At least one filter in each such stream (8.1.1.5) shall be equipped with a device for l measuring differential pressure that shall be read monthly. Filters shall be changed when readings deviate from specification values (.8 to 4.0 inches WG) or following evidence of damage.
License No. SNM-960 Docket No.70-734 Sect. No.
- 8. 0 Page A-8-1 AppendixA Date 11/19/98 Amends Sect.(s) 81.1.6
l 3.6 EMERGENCY EQUIPMENT A vehicle is available to Radiation Safety and can be equipped quickly with a supply of protective clothing, first aid equipment, respiratory protection equipment, and portable instrumentation and sampling equipment for use during emergencies. Emergency equipment also is stored in selected areas on site.
l 3.7 INDUSTRIAL SAFETY EQUIPMENT In conjunction with the radiation safe:y program at VNC, industrial health and safety of VNC l
personnel also are emphasized. Some of the protection facilities and equipment which are available include portable extinguishers, sprinkler systems, and a wide range of typical industrial safety equipment.
3.8 CRITICALITY ALARM SYSTEMS In any Vallecitos Nuclear Center area in which special nuclear material containing more than 500 grams of U-235 is used or stored and does not otherwise qualify as a "subcritical area" as defined l
in Section 3.17 of Appendix A, a monitoring system, including gamma-or neutron-sensing l
devices which will energize an audible alarm in the event of criticality, is installed and maintained. The system in use on site is described in the following paragraphs.
3.8.1 Gamma Detection System This monitoring system consists of three commercially designed and manufactured gamma detectors which monitor each designated area. Two of the three detectors which are subjected to a dose rate in excess of preset alarm points will cause an alarm condition. Failure of any detection circuit component which would prevent criticality detection activates a warning light on the unit. Failure of any signal-producing component is detected during the monthly test.
The system is capable of energizing the alarm when the radiation level at a distance of 2 meters from the special nuclear material is equivalent to 20 rads of combined neutron and gamma radiation within one minute.
i License No. SNM-960 Docket No.70-754 Sect No.
- 3. 0 Page 3-5 Date !VI9/98 Amends Sect.(s) 3.8
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g SHOP SK98023 Figure 6.2. Building 102 Main Floor - Radioactive Materials Areas License No. SNM-960 Docket No.70-751 Sect. No. Fleure 6.2 Page 6-9 Date
!I//9/98 Amends Sect.(s) Fleure 6.2
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Attachment A to VSS 7.2 Bases for the Stack Action Levels in VSS 7.2 i
The stack release action levels are defined as the release rates for each radionuclide group (noble gas, I-131, beta particulate, or alpha particulate) at which action should be taken to reduce the release rate. The design basis for setting the action levels is the requirement to j
maintain doses to members of the public from airborne releases to a maximum of 10 mrem per year. The method for establishing these action limits is described below.
10CFR20, Appendix B, Table 2, Column I gives airborne radioactive material concentration limits for releases to the general environment. Inhalation of one of these radioisotopes at that concentration continuously over the course of a year would produce a total effective dose equivalent of 50 millirem. Therefore, the release rates from the effluent stacks at VNC must be controlled to a level which will not exceed 20% of the 10CFR20 effluent concentrations at the site boundaries. Annual average release rates are converted to boundary concentrations by a dilution-dispersion factor. Dilution-dispersion factors are calculated from the measured meteorological conditions for a year's period (or more). Consideration also is given to concurrent releases from the other stacks on site.
The action level for the noble gas releases from the NTR stack is selected as the rate which would give an annual average concentration of Ar-41 at the site boundary of 20% of the concentration limit, further divided by a factor of two for other stack releases. Ar-41 has been shown to be the predominant noble gas in the stack effluent (Climent,1969). Fission-produced noble gases are a minor fraction unless fuel material is exposed to the effluent air.
Ar-41 is produced by the neutron irradiation of the air passing through the reactor. The basis for the Building 102A stack noble gas action level is selected conservatively as 10% of the concentration limit for Xe-133 and further reduced by a factor of two.
The action levels for all other isotope groups are selected as 10% of the concentration limit for the restrictive, credible isotopes of each of the isotope groups: I-131, Sr-90, and Pu-239.
These, too, are reduced further by a factor of two for other stack releases. The release limits are specified as release rates ( Ci/sec); this makes the limit independent of the stack flow rate. A limit expressed as a concentration ( Ci/ml) is dependent on the stack flow rate.
However, radioactive concentrations are easily determined and therefore commonly used in reporting effluent releases.
The stack flow rates fluctuate, sometimes by design and sometimes randomly. For example, the NTR flow depends on the position of the cell door; Building 103 is designed to have i
reduced flow during non-working hours; Building 102A has multiple fan combinations but usually operates in a fixed configuration. The flow in all filtered systems varies as the dust loading on filters increases and as containment systems are changed. The following stack t
A-1
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flow rates are the anticipated highest nominal flow rates or weighted average flow rates (where applicable) used for limiting concentrations and calculating releases:
1 Stack Location Flow Rate. cfm Building 102A 45,000 Building 103 30,000 Building 105, NTR 1,800 GETR 6,800 Waste Evaporator 3,600 Hillside Storage, Sandblast 2,000 Hillside Storage, Bunker 27,000 i
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The applicable effluent concentration limit values from Appendix B, Table 2, Column 1 of
.10CFR20 are given below:
10CFR20 Effluent Limiting Concentration Limit, Release Category Isotope Ci/ml Noble Gas:
- j Beta-Gamma Particulate 1.00E-12 The 102A noble gas inventory consists of Xe-133 and Kr-85 only, since all fu : ba:mled has at least 90 days decay.
The NTR noble gas inventory available to the boundary has been found to be primarily Ar-41, which is an activation product of air. Fission products would be of concern in the event of fuel failure, an abnormal condition.
" 'Ihere are several isotopes with more restrictive limits, but they can be shown to be insignificant fractions l
of the typical mix of alpha emitters found at VNC.
"* Unidentified isotopes, where several natural, transuranic, and other rare elements are known to be absent.
These are mainly alpha emitters which would be accounted for in the alpha analysis.
A-2
The dilution-dispersion (x/Q) factors and reduction factor to account for releases from "other
- stacks" are given below:
"Other stack",
Stack Location x/Q, sec/ml reduction factor Building 102A 8.25E-11 2-j Building 103 8.25E-11 2
Building 105, NTR 3.48E-11 2
GETR-8.25E-11 2
Waste Evaporator 8.25E-11 2
l Hillside Storage, Sandblast 8.25E-11 2
Hillside Storage, Bunker 8.25E-11 2
The dilution-dispersion factors were calculated for two stacks, the NTR and Building 102A.
The NTR factor was calculated from measured meteorological histories for a two-year period in 1976 and 1977. The Building 102A factor was later calculated for measured 1
meteorological histocies over a five-year period. For convenience, the other stacks on site -
were assigned the same x/Q value as the 102A stack. This is a conservative action since the
- 102A stack is nearer the site boundary than any other stack.
Using the above informatien, the 50 mrem /yr annual average release rate limits for the site stacks can be calculated as the concentration limit divided by the x/Q and divided by the
~"other stack" reduction factor.
Annual Average Release Limit, pCi/sec (50 mrem /yr)
Stack N. Gas Halogen Alpha Beta 102A 3.03E+03 1.21E+00 6.06E-05 6.06E-03 103' N/A 1.21E+00 6.06E-05 6.06E 105, NTR 1.44E+02 2.87E+00 1.44E-04 1.44E-02 GETR.
N/A 1.21E+00 6.06E-05 6.06E-03
-WEP N/A 1.21E+00 6.06E-05 6.06E-03 HS SB N/A 1.21E+00 6.06E-05 6.06E-03 HS Bunker N/A 1.21E+00 6.06E-05 6.06E-03
- These release limits (except the NTR noble gas) are divided by ten and converted to the
- weekly release rate action levels and, for convenience, concentration limits for Table 1. The NTR noble gas concentration limit is based on a typical operating week of 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> at 1,800 cfm.
9 A-3
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Table 1. Stack Release Action Levels Nominal N. Gas Halogen Alpha Beta Flow Rate, Ci/wk mci /wk Ci/wk Ci/wk i
Stack cfm Ci/cc pCi/cc pCi/cc pCi/cc 102A 4.50E+04 183 7.33E+01 3.67E+00 3.67E+02 l
1.4E-05 5.7E-09 2.9E-13 2.9E-11 l
103' 3.00E+04 N/A 7.33E+01 3.67E+00 3.67E+02 N/A 8.6E-09 4.3E-13 4.3E-Il 105, NTR 1.80E+03 18 1.74E+02 8.69E+00 8.69E+02 1.9E-04 3.4 E-07 1.7E-11 1.7E-09 l
GETR 6.80E+03 N/A 7.33E+01 3.67E+00 3.67E+02 l
N/A 3.8E-08 1.9E-12 1.9E-10 WEP 3.60E+03 N/A 7.33E+01 3.67E+00 3.67E+02 N/A 7.lE-08 3.6E-12 3.6E-10 HS SB 2.00E+03 N/A 7.33E+01 3.67E+00 3.67E+02 N/A 1.3 E-07 6.4E-12 6.4E-10 HS Bunker 2.70E+04 N/A 7.33E+01 3.67E+00 3.67E+02 l
N/A 9.5E-09 4.8E-13 4.8E-11 l
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- The NTR noble gas concentration limit during non-operating times, i.e., when the reactor is l
shut down and the cell door can be open, is set at 2e-6 Ci/cc.
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A-4
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Enclosura 2 l
I VNC Meteorology 5-year Summary (1979 to 1983). Wind Rose Basis for Worst Case Sector I
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l Sector 9. South, Distance to Fence = 386 met.e_rs_ _
1979 1980*
1981 1982 1983 Pasquill Wind Percent Number Percent Number Percent Number Percent Number Percent Number Stability
- Speed, of Houra in of Hours in of Hours in of Hours in of Hours in Type m/s in Sector Sector in Sector Sector in Sector Sector in Sector Sector in Sector Sector A
42 0
0 0'
0 0'
0 0
0 A
>2-3 0.012 1
0.011 1
0.114 10 0.0f 6
A 4-7 0.299 26 0.091 8
0.285 25 0.081 7
A 8-12 0.081 7
0.023 2
0.148 13 0.058 5
0T08II 7
A 13-18 0
0 0.011 1
0.297 26 A
19-24 0
0 0.011 1
0.057 5
0.023!
2 A
>24 OI~~0' O
O O.
0 0 023I 2
8 0-2 O!
0 0i O
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0 Og 0
B
> 2-3 0.0127 1
0.023j 2
0.114 10 0.0584 5
3 8
4-7 0.173 15 0.297l 26 0.263 23 0.139!
12 i
0.263f 23 0.16 7 9
8 8-12 0.161 14 0.103!
9
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B 13-18 0.023 2
0.046I 4
0.103i 9
0.128l 11 B
19-24 0
0 0
0 0.034 3
8
>24 0.023 2
0 0
0.034 3
0.035i 3
O.012I 1
C 42 0
0 04 0
0 0
0 0
C
>2-3 0
0 0.16D 14 0.091 8
0.035 3
C 47 0.023 2
0.423 37 0.228 20 O.383 33 C
8-12 0.334 5
0.4 35 0.445 39 0.278 24 C
13-18 0.058 5
0.228 20 0.251 22
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0.209 18 C-~
>24 OI i) 19-24 O!
0 0.011 1
0.011 1
0.058 5
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0 5237 2
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0.03 ~
0 D
4-7 0.046 4
0.24 21 0.24l 21 0.255 22 D
8-12 0.334 29 0.388 34 0.502l 44 0.464 40 D
13-18 0.023 2
0.286 25 0.206j 18 0.371 32 D
19-24 0.023 2
0.046 4
0; O
0.012 1
D
>24 0.012 1
0.011 1
O!
0 0
0 E.
0-2 0
0 O
0 0
0 O!
0 0.103p E
4-7 0.046 4
0.24 21 0.171 15 0.128}
11 E
2-3 0
0 9
0.091 8
0.361 31 E
8-12 0.288 25 0.266!
25 0.297 26 0.209[
18 E
13-18 0.184 16 0.149F 13 0.091 8
0.116]
10 E
19-24 0.035 3
0.023 2
0
-0 0l 0
' 24 OI O
O O
Oi 0
Oi 0
E
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F 0-2 Oi 0
0 0
0; O
O O
F
>2-3 O!
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_ 0114 10 0.126l 11 0.0584 5
F 4-7 01 0
0.217 19 0.194 17 0.186 16 F
8-12 0.035!
3
[
~ 0.137 12 0.126 11 0.104 9
1 F
13-18 0.115I 10 0.034L 3
0.011 1
0.023 2
F 19-24 Oi 0
t O!
0 0-0 0
0 F
>24 O!
O I
Oi 0
0.01TI 1
0 0
G 0-2 2.821[
245 2.981[
261 _ _ 1 066 ( 181 2.992 ( 258 G
>2-3 O!
0 0]
O 04 0
O!
O 0.012[j 0
0 OL 0
0 0
G 4-7 0
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8-12 1
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13-18 04, 0
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19-24 0
0 Oi 0
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Oi 0
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Number of Good Records: }
l 8759 i 8759l
! 8623 8687b
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- The summary records for 1980 are no longer ava_itable. Computer system changes since 1980 would require a significant effort to rerun the 1980 meteorological esaluation.
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