ML19242A988
| ML19242A988 | |
| Person / Time | |
|---|---|
| Site: | University of Missouri-Columbia |
| Issue date: | 07/05/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19242A980 | List: |
| References | |
| NUDOCS 7908070261 | |
| Download: ML19242A988 (7) | |
Text
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/_p* ** coq [o UNITED STATES y 7,,, y j NUCLEAR REGULATORY COMMISS!ON
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/, C WASHINGTON. c. C 20555 SAFETYEVALUATIONBYTHEOFFICEOFNUCLEARREACTn'REudLhTIOr.
SUPPORIlHb AMENUMENT NO. M Id LICi { E.
UNIVERSITY OF MISSOURI RESEARCH REACTOR UNIVERSITY OF HISSOUkl - COLUMBIA DOCKET uu. 50-leo Introduction By letter dated Feoruary 15, 1977, as supplementeo by le:
s catec March 27, 1978 and Marcn 16, 1979, the University of Missu - Columbia (the licensee) proposed an amencment to Technical Specification 3.7.a appenced to Facility Operating License No. R-103 for tne University of Missouri Researen Reactor (NURR). The proposed amenonent would change the limitations on gaseous radioactive releases from the researen reac-tor f acility.
Discussion The licensee has stated that by increasing operation from 90 to 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> per week at a 10 tiegawatt power level to near continuous operation, the resulting increased total activity released from the facility exnaust stack will bring the yearly avereged release concentration of Argon-41 close to the present Tecnnical Specification 3.7.a limit of 250 times the maximum permissible concentration (ItPC) as given in Appendix B, Table II, Column I to 10 CFR Part 20, when averaged over a year.
Since September 1977, the li-censee has reduced the Argon-41 releases by removing a pneumatic tuce test facility from service in order to meet the present Technical Specification 3.7.a during continuous operation. The licensee considered that Technical Specification 3.7.a was unnecessarily restrictive, and proposed to ameno this specification to limit the maximum concentration for all racioactive materials in gaseous effluents (noole gases, tritium, particulates anc halogens) from the f acility exnaust stack to 1000 times MPC, wnen averaged over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period.
In a letter datec August 4, 1977, the NRC requestec auditional information to support this proposed amenoment. On Marcn 27, 1978, the licensee submitted the additional information an:
(1) the bases for the proposed Cnange, (2) the stack monitor, (3) a sume.ary of yearly stack releases and (4) changes in facility operation that would have impact on the gaseous effluents.
By letter dated March 16, 1979, the licensee succitted accitional infomation on the proposed change to Technical Specification 3.7.a.
The licensee com-mitted to place TLD monitoring stations at the following locations arounu his f acili ty:
one station on each of four outsica walls of the reactor culloing, four stations at a distance of appoximately 150 meters from the cuilcing (the prevailing wind cirection ano 90*,180' ano 270* from ini cirection),
one station at Dalton Research Center in the Researen Part area and one station on University of Missouri property near the nearest resicence. The 79080 0 $ b
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-Z-licensee estimatec that tne annual exposure from gar is ef fluents at pres-ent operating levels (1600 Curies Argon 41 per year)
' 2 mrem per year total bocy cose at the nearest resicence. This resicenc 760 meters from tne reactor building based on an aerial pnotograph measurement. Tne licensee provicec cata from his environmental monitoring program on concen-trations of Argon 41 in the air at tne sice of the reactor builcing downwind of the stack. The concentrations of Argon 41 in the air were measured to oe half the maximum pemissible concentration MPC for Argon 41 in air in Table II to Appencix 3 to 10 CFR Part 20 for unrestricted areas. The minimum level of cetection for Argon 41 for these measurements was less tnan tne measurec concentration for Argcn 41.
Accitional measurements of concentrations of Ar-gon 41 at 75 meters from the reactor building wnicn is wi thin the exclusion councap were less tnan the minimum level of cetection for the measurements (4x10- 1.Ci/cc). This is one tentn of an MPC of Argon 41 in air in unrestricted areas. These measurements were mace while the reactor was at full power (i.e.,
10 megawatts).
Safety Evaluation We have perfomed an independent evaluation of the licensee's pro-posed amendment to Technical Specification 3.7.a.
Our evaluation
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consisted of the following:
(1) a review of the information provicec Dy the licensee in his February 15,1977, March 27,19 78, and the MURR - Reactor Op-erations Annual Report 1977-78, Septemoer 1978 submittals, (2) a review of the racicactive waste treatment and effluent control systems descrioed in tne licensee's Hazard Summary Report (HSR), including amencments througn 3eptemuer 1978, and (3) a review of the metnocology used to calculate an annual cverage
_ relative concentration (x/0) applicable to tne MURR site at Columbia, Missouri.
We found that the proposed Technical Specification 3.7.a to limit the maximun, concentration for all radioactive material in gaseous effluents from the facility exhaust stack to 1000 times MPC, wnen averagea over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, would exceec the limits of 10 CFR Part 20.106a anc, therefore, was un-acceptable. The staff consicered an alternate cnange that is evaluated oelow.
During normal and anticipated operational occurrences, the gaseous effluents from the MURR are monitored and released via the f acility exhaust stack.
Tacle 1 provides a summary of the operating experience for the NURR, incicating the racioactive gaseous effluents reported during six years of operation, July 1972 througn June 1978. The principal racionuclice in gaseous effluent is Argon-41 (greater than 99%) and tne principal racionuclice in liouia effluents is ;ritium (greater than 99t). Argon-41 is generated by neutron activation of cir, and tritium by tne neutron activation of ceuterium in tne cooling water.
The amount of Argon-41 and tritium released from the f acility is cirectly 469 2]8
proportional to the power generated by the eactor.
For comparison, we calculated the Argon-41 and tritium annual rr.. eases based on effective full power days. As shown in Table 1, the tritium releases are expected to stabilize at approximately 0.1 curies per effective full power day, as a result of the increased operating capacity. Table 1 also shows that the licensee nas acted to reduce the Argon-41 releases from the facility, based on the reduction from 8.26 curies to 6.28 curies per effective full power day during the past years. We conclude that the licensee is making a reasonable effort to maintain releases cf radioactive materials in gaseous effluents as low as is reasonably achievable, pursuant to 10 CFR Part 20.l(c).
We used meteorological data collected at the Callaway Plant, Units Nos.1 and 2, located near Fulton, Missouri, approximately 30 miles ept of the MURR site. Tnese data were collected between May 5,1973 and May 4,1975, and are reasonab.ly representative of long-tem conditions expected at the MURR site. The highest offsite annual average relative concentration (X/Q) value was calculated by the staff to be 3x10-4 seconds per cubic meter at a distance of 150 meters from the MURR facility. This is the exclusion bound-ary at the MURR facility which is described in the MURR Safety Evaluation, Amendment No. 8, dated February 8,1978.
We calculated that the maximum concentration in the facility exhaust stack discnarge for all radioactive isotopes otner than particulates and halogens with half-lives greater than 8 days should not be greater than 350 times MPC, wnen averaged over one year. The value of 350 is the average ci-lution factor that would reduce the maximum calculated annual average concen-tration of Argon-41 at the exclusion boundary to one MPC for tne unrestricted a re a.
The release rate is based on an annual flow rate of 9.63 cuoic meters per second f rom the f acility exhaust stack as provided in Addendum 2 to tne Hazard Summary Report, dated May 1966, for the MURR.
The unrestricted area for the MURR f acility is tnat area outside the walls of the reactor building. The licensee has measured the concentration of Argon-41 at the sida of the building downwind of the stack at roof level wnile operating at full power. Based on these measurements, the maximum concentra-tion in the stack discharge for Argon-41 should not be greater than 360 times MPC for the concentration of Argon-41 in the unrestricted area to be less than one MPC.
This is cased on 6.28 curies of Argon-41 per effective full power day. Based on this, we conclude tnat a gaseous concentration in the f acility exhaust stacx for all radioactive isotopes other tnan partic-ulates and halogens with nalf-lives greater tnan 8 aays that does rtot exceeq l
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- 350 times MPC, *nen averageo over one year, snould meet the recuirements of 10 CFE Pa rt 20.106( a ). Because tne measurements of Argon-41 were mace at nomal wind concitions without tne wind speed or vinc stacility class Dei ng measured, we have askee the licensee to place TLus around tne f a-cility to measure tne annual cose from Argon 41 releaseo f rom the f acility.
The licensee has agreec to place four TLDs arounc tne reactor Duilcing; four at the exc'usion Douncary, one at Dalton Research Center and one on Univer-sity of Missouri property near the nearest resiaence. The TLDs will De lo-cated about one meter above tne ground anc will be replaced quarterly. If these TLDs incicate that the maximum concentrations of Argon 41 in Tecnni-cal Specification 3.7.a is too nign to meet the requirements of 10 CFR Part 20.106(a ) the Speci fication will De revi sed. The licensee will incluce the measured annual doce from Argon-41 from these TLDs in his Arnual Report to NRC.
In addition, wo calculated that the instantaneous concentration of the facility exnaust stack for all radioactive isotopes otner tnan particulates anc halogens witn half-lives greater than 8 cays should not be greater tnan 3500 times MPC at any time. This limiting condition for operation provices reasonable assurance that radiation les els to an incivicual in the unre-stricted area, at or beyond the exclus on boundary, will not De exposed to a whole body cot > at any time exceeding the limitations of 10 CFR Part 20.105 wnile providing the licensee operationti flexibility for unusual operating conditions.
The MURR research reactor is located about 0.5 miles south of the southern border of the residential area of Columbia, Missouri. Between 0.5 and 1.0 mile from the reactor facility are approximately 5,700 people of the 58,000 people of Columbia. This is taken from Section 5.0 in Addendum 3 dated August 1972 to the MURR Hazards Sumary Report and based on the 1970 population census. We have esti-mated the radiation exposure to the total population of Columbia from the reactor's present operations to be about 10 man-rem / year. Based on an estimated present population census, the radiation exposure may be about double the above 10 man-rem /
year or 20 m m-rem / year. This small amount of exposure is a minute fraction of the exposure tothe population from background radiation and does not seem to warrant any additional efforts by the licensee to educe radioactive releases from the facility.
Since the anticipated population dose is calculated so small, we will only recuire the licensee to perform confimatory calculations based upon records of exposure to ILD's placed around the facility over an operating year and a more accurate up-to-date description of the population density out to 10 miles from the reactor facility, including Columoia, Missouri. Beyond the10 miles distance the short-lived Argon-41 has decayed and been dispersed to insignificant concentrations in the air. The licensee, based on the confimatory calculated radiation exposure to the population, is to detemine if any additional changes to the facility are economically warranted using the 51,000 per man-rem (Section II.D of Appendix I to 10 CFR Part 50) for the so' l cost of radiation exposure reduction. The results of this value/imca
.scessment is to be provided to the staff for review and approval.
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Based on the above, we have concludec that the licensee's proposed Tech-nical Specification 3.7.a is not acceptacle. The licensee has not prov1aed data ta justify increasing the present limi ts in Tecnnical Specification 3.7.a for par *.u lates and nalogens with nalf-lives greater u
than 8 days. Tecnnical Specification 3.7.a for all other racicactive iso-topes snoul.d be amenced to increase the maximum release concentration to De averaged over one year from 250 times MPC to 350 times MPC and the maximum instantaneous release concentration from 2500 times MPC.to. 3500 times MPC, at any time, as discussed in tne evaluation above. Ne discussed these cnanges with the licensee, and the licensee has agreed to inese moci-fications.
Conclusion The staff has concluced, based on the considerations discussed aoove, tnat:
(1) because the cnange does not involve a significant increase in the prod-aDility or consecuences of accicents previously consicered and does not in-volve a significant cecrease in a safety margin, the change aces not involve a significant hazards consicera' ion, (2) there is reasonable assurance that the health and safety of the pudic will not be enaangered oy operation in the proposed manner, and (3) such activities will be conoucted in compliance with the Comn'ission's retulations and the issuance of this amendment will not be inimical to the common oefense and security or to tne healtn and safety of the puolic.
'tovironmental Impact Aporaisal We have detennined that the amendment modified by the staff and agreed to by the licensee does not authorize a change in effluent type nor an increase in power level. As described above, the amendment would allow an increase in the maximum annual concentration of Argon-41 in the stack discharges from 250 times MPC to 350 times MPC (i.e., from 3037 to 4252 curies of Argon-41 per year). Argon-41 is the principal isotope released in gaseous effluents from MURR. We calculated the annual average relative concentration (X/Q) for continuous stack releases and ground-level conditions to the nearest residence at 760 meters from the stack to be 2.4x10-5 sec/m3 Based on the methodology provided in Regulatory Guide 1.109 (Rev.1), wa calculated that an indivicual located at the nearest resicence.wJuld maiva e annud-average dose of 13 mrem per year total body based on '.he present rele8n 3s of Argon-41 from M'JRR (i.e.,1925 curies per yea,- for 1917 to 1 6.
The licen-see calculated a dose rate of 32.2 mrem total Docy per year basea on 1600 cur-ies of Argon-41 released per year which is what they expect for tneir present operations. The change to Tecnnical Specification 3.7.a would allow tne li-censee to release up to 4250 curies of Argon al per year. This would De an annual average dose to an incividual at tne nearest resicence of 29 mrem per year total bocy. We would expect, on present operations, tnat the MURR f acil-ity would not release more tnan 3015 curies of Argon-41 per year. Tnis is based on 100% continuous coeration at full power for the year and 3.20 curies of Argon 41 releases per effective full power day. The present operation is only at 6.28 curies of Argon-41 per ef fective full power aays.
At 3015 curies Argon-41 per year, the annual average cose to an indivicual at tne nearest 88 %
ma
-. resicence is 21 mrem total cocy per year. By comoarison, the concentration lim-its of 10 CFR Dart 29 recuire that an indivicual locatec in the unrestrictec area De limited to a total body dose less than 500 mrem /yr. Tne staff has also calculated the annual average relative concentration (X/Q) for continuous stack release and ground level conditions to tne Dalton Research Center at 350 meters from the stack to be 8.0 x 10-0 sec/m3, Compared to the X/Q value calculated at the nearest residence location, tnis is higher by a factor of 3.3.
However, the potential increase in dose to personnel at the Dalton Research Center is offset by a shorter occupancy time 7.t the location (i.e., a decrease by a factor of 4 wnen considering a 40-hour workweek comoared to a 163-hour residence occupancy time). The staff, therefore, concludes that tne annual average dose to personnel at the Dalton Research Center is not signi-ficantly different from those analy;:ed above for an individual at the nearest residence location. Although the amendment allows up to 40%
increase in the amount of Argon-41 released, the increased dose impact resulting from this change will be a small fraction (less than 2%) of the dose limitations of 10 CFR Part 'O.105.
Conclusion anc 3 asis for Heaative Declaration On the basis of the foregoing evaluation, it is concludec tnat there would be no significant environmental impact attributable to the proposeo action.
Hav-ing mace this conc'.asion, tne Commission has further concluded that no envi-ronmental impact r,tatement for the proposed action need be prepared and that a negative declaration to this ef fect is appropriate.
Dated: July 5, i979 PGURBRl[lyyi
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Table 1 SUM"ARY OF ODERAT:N5 EXPERIENCE 0R THE UNIVERSIT' OF h!55CURI RESEARCh REACTOR t rURR )
UO;tET NO. EU-ioc Gaseous Effluent Release Data (in Curies / year)"
Radioactive July 1972-July 1973-July 1974-July 1975-July 1976-July 1977-Waste June 1973 Jun: 1974 June 1975 June 1976 June 1977 June 1978 Total fioble Gases 1055 970 1790 1734 1734 1925
( A-411 Total Iodine-131
<4 x 10-' 2.4 x 10~# 1.6 x 10" 8 x 10'# 1.3 x 10~#
Total Halogens
<0.01 (0.006 0.006
- 0. 01 6 0.11 Total Particulates
<0.006 0.001
<0.001
<0. 001 0.002 Total Tritium 1.8 3.6 4.8 26.24 Facility Ooeratine Conditions Maximum. Thermal 5
5 10 10 10 10 Power (MWt)
Annual Megawatt Days 1047 960 2168 2100 2100 3065 Facility Operating 0.57
- 0. 53 0.59 0.58 0.57
- 0. 84 Capacity b
A-41 Releases 5.04 5.05 8.26 8.26 8.26 6.28c (curies per
~
~
Effective Full Power Day)
Tritium Releases 0.008 0.017 0.023 0.086 (curies per Eff-ective Full Power Day) a - Reactor Operations Annual Report for MURR, Jtly 1977 to June 1978 (Docket
- No. 50-186) and a tummary of MURR airborne r leases provided by letter, dated March 27, 1978.
b - Increase due to increasing the power level.
- Decrease due to removing a pneumatic tube from service.
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