From the 2001 Workshop
ask the NRC
1. Using the historical
meteorology that's used in the ODCM for estimating dose and end of year dose
assessment for the annual radiological effluent report, how often should the
meteorology be updated, is one year of data adequate or should X number of years
be averaged. If so, how many years?
2. On site recreational doses
for the general public - are these necessary, and why or why not (10CFR20, 100
millirem for general public)?
3. Total estimated errors for
the annual radiological effluent report - propagating all errors by taking the
particle derivatives of all inputs in determining the curies released and dose
comes out as high as 1000%. Is there a recommended NRC acceptable method for
determining the error to be used in the effluent report?
4. For reporting the offsite
dose in the annual report, should all pathways be included? For example: if
there are no milk pathways within 5 miles of the site, should the milk pathway
be included in the dose?
5. TMI had high tritium and had
to evaporate to get rid of it after their accident. Being on the coast, they
probably had fairly good meteorology. If an inland plant wanted to do the same
thing, and build a stack to take advantage of mixed mode release, would this
require a public hearing?
6. What is additional guidance
(beyond "unplanned or uncontrolled" given in RG 1.21) for reporting of abnormal
7. To avoid numerous trivial reports, is a threshold allowed for reporting
abnormal releases? What should be the threshold?
8. What does NRC do with reports of abnormal releases?
9. Are the number of abnormal release events being used for performance
10. Can a plant be penalized for reporting an excessive number of abnormal
releases because of a low threshold?
11. We have a building onsite that was converted from a warehouse-type structure
to contain a carbon dioxide decontamination/blasting unit. Even though the decon
unit was intended for equipment and scrap metals with a maximum of only a few
tens of thousands of dpm/100 cm2, the unit has not been operated because the
building has no installed ventilation system and no installed radiological air
monitoring equipment. Although the potential for release of airborne radioactive
material was low, and the decon process was to be filtered through portable HEPA
units, it was felt that, because of the lack of installed ventilation and air
monitoring equipment, there was the possibility for unmonitored release. This
building is not identified as an effluent pathway.
Can this decontamination unit be operated in its current configuration and
remain within regulatory bounds?
12. The reactor buildings onsite each have an equipment hatch (EH) for loading
and unloading equipment during reactor unit outage. There are specific
evolutions, such as fuel movement, during which the EH is required by Technical
Specifications to be closed. The EH remains closed for much of the remainder of
the outage. However, there are periods during which the EH remains open. During
some time periods in which the EH is open, air sampling identifies small amounts
of activity on the outside of the EH. Activity has been identified even when the
reactor building purge is operating. In all likelihood, outside wind currents
draw small amounts of air out of the reactor building via the EH. While it is
believed that this activity "falls out" before leaving site, the activity is
accounted as having been released. The reactor building purge, which discharges
to the unit vent, is an identified effluent pathway and is continuously
monitored and sampled.
Has this phenomenon been observed at other sites? What is the regulatory
perspective regarding the "release" of activity in this manner?
13. If during an RFO, gaseous release process flow is secured, do you continue
to run your sampling system? The prudent answer would be "Yes", in the event
that: (1) the isolation wasn’t fully effective; (2) you had some unknown input
to the system; or, (3) you had to immediately start the system to respond to
some event. What do you assume for the ratio of sample flow rate to process flow
rate, which technically becomes infinity?
14. If you measure NDA on noble gas grab samples, but have sporadic low level
increases in PRM response, do you still assume no release, since there was no
detectable activity in the sample by which to weigh/partition releases?
15. How do you determine noble gas conversion factors in which the PRM is
exposed to a mix that is dominated by short –lived nuclides (e.g., Kr-90,
T1/2=32 sec), which are absent from the mix when the gas sample is analyzed by
gamma spectroscopy? The PRM is responding to a concentration that may be 10-20
times higher than what remains in the grab sample upon analysis. Do you adjust
the PRM to account for the unknown/undetermined activity? Do you calculate the
conversion factor based on only the identified/measured activity, since that is
what is being released, and that which would contribute to offsite dose?
16. Do rigorous, hard-fast definitions of surveillance frequency intervals apply
to collection of REMP samples? Do the hard-fast ‘rules’ of <1.25 * interval
between successive samples, and <3.25 between third successive samples apply?
17. Inspection Procedure 71122.01 defines dose values below the design
objectives of Appendix I to 10 CFR Part 50 and 40 CFR Part 190 as ALARA. 10 CFR
20.1101 (b) states: "The licensee shall use, to the extent practical, procedures
and engineering controls based upon sound radiation protection principles to
achieve occupational does and doses to members of the public that are as low as
is reasonably achievable (ALARA)".
a. Would the NRC ever consider using a three year rolling average on releases to
determine if a plant is operating in an ALARA manner?
b. If a plant has an increase in release rates from the previous year but below
the plant's Technical Specifications and ODCM limits, would the NRC
consider that this plant is non-ALARA? If the answer is yes, then at what
fraction of an increase would be considered non-ALARA?