ML20115F765
| ML20115F765 | |
| Person / Time | |
|---|---|
| Site: | 05000187 |
| Issue date: | 04/09/1985 |
| From: | Benveniste J NORTHROP RESEARCH & TECHNICAL CENTER |
| To: | Thomas C Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8504220020 | |
| Download: ML20115F765 (7) | |
Text
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NORTHROP 049jbp2 9 April 1985 Dr. C.0. Thomas, Chief Standardization and Special Projects Branch Division of Licensing, NRR U.S. NRC Washington, DC 20555
Dear Dr. Thomas:
In response to your request for additional information regarding the Northrop Decommissioning Plan, we submit the following:
1)
The monitoring equipment for dismantling and decommissioning, listed in Section 2.1, includes many dose rate meters with levels down to 0.1 mr/hr.
The decontamination operation will ensure that the facility complies with the surface activity limits of Regulatory Guide 1.86.
Table III of the Northrop Decommissioning Plan prevides 2
acceptable surface contamination limits in terms of dpm/100cm,
However, the aforementioned listed instruments that are to be used to measure surface contamination levels do not appear to provide for this unit of measurement.
If additional instruments are to be supplied to read-out in counts / min., describe your procedure for converting this read-out to dpm/100 c/-
During decommis.,cing, surface contamination will be monitored with suitable a..
s, beta and gamma sensitive instruments.
The s e instrument detect individual events so direct measurement of dete:ted counts per minute is possible. From there, a considerati n of the subtended solid angle and the det e c t o r ef ficiency will convert counts per minute to disin t egrations per minute.
In addition, we intend to calibrate these detectors with sources traceable to NBS.
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.P 2)
Please describe how pipes, drainlines and ductwork will be surveyed for contamination on the interior, to assure conf ormance with Regulatory Guide 1.86 limits.
If no appropriate access points for these surveys are available, what survey plan would be used to make the measurements necessary to show potential contamination of the interior of pipes, etc.
The procedure for surveying pipes, drain lines, and ductwork will be basically the same: The nearest accessible locations will be surveyed with suitable instruments and wiped for removable contamination as far inside as can reasonably be reached. These locations will include the ends of accessible pipes, the interior surfaces of inlet and outlet vents, and the water traps and exit points of drain lines. If no significant radioactivity is f ound at the entry and exit locations, a
" wipe" will be pulled through representative pipes, drain lines, and duct work to determine internal contarination
. levels.
If, on the other hand, contamination exceeding limits established by Regulatory Guide 1.86 is found, each such pipe, drain line, and duct work will be " wiped" through its entire length.
3)
. The staff-position for decontamination for release for unrestricted use or unrestricted access is Regulatory Guide 1.86 or a survey meter measurement of 5 r/hr above background at 1 meter. Alternatively, demonstration that the residual radiation from the decommissioned facility provides a maximum exposure to an individual of less than 10 mr/yr, considering limited occupancy in the vicinity of the radiation, is acceptable. Please indicate the manner in which you
'will apply these alternatives to your decommissioning plan to be consistent with staff criteria.
In order to comply with Regulatory Guide 1.86 and to measure radiation levels in the range of a few micro-Roentgens per hour above background Northrop and the decommissioning contractor have assembled an assortment of sensitive, portable radiation instruments. These include 17 pancake-type G-M detectors, 5 alpha counters, and 4 micro-Roentgen meters. We also note that 5 r/hr for a 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> year (40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> per week x 50 weeks) is 10 mr/ year. Thus, the two numbers are the same if one agrees that up to 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> per year is consistent with the term
" limited occupancy".,
e 4)
Although your instrument listing in Section 2.1 includes a Victoreen 440 ionization chamber, the sensitivity of this instrument is not suf ficient to indicate a dose rate of 5 r/hr above background.
Please state your intention to provide an instrument, such as a pressurized ionization chamber, that has the capability to meet the appropriate sensitivity requirements necessary to assure release for unrestricted access in accordance with staff requirements.
The instruments mentioned in the answer to question #3 have sensitivities to indicate a dose rate of 5 pr/hr above background.
5)
Please describe the method you will use (e.g., GeLi spectrometer) to identify radioactive nuclides found in swipes, core samples, etc., that will be taken during dismantling.
During dismantling wipes, core samples, scrapings, and liquid samples will be sent to an independent certified laboratory for radionuclide identification.
6)
What contamination thresholds will be used to identify and dispose of facility equipment and components as radioactive waste. Describe the measurement procedures that will be used to determine when these limits are exceeded.
Any equipment which exhibits contamination levels less than 0.1 of those limits specified in Regulatory Guide 1.86 will be kept. Equipment exhibiting levels in excess of 0.1 of these limits will be decontaminated to acceptable levels or disposed of as radioactive waste.
The instruments described previously will be used to monitor these levels.
7)
Part 3 of Section 4 of the Environmental Report in Support of the Decommise,ioning states, 'A competent and well trained health physics team will monitor all dismantling operations.' Will HP functions be provided solely by Northrop or by Northrop and contractor personnel?
How large an HP staff is planned for the project.
Health Physics functions will be provided by both Northrop and contractor personnel.
This combined Health Physics staff will consist of one corporate radiation safety officer on site, a contract radiation saf ety of ficer consulting, a certified Health Physicist on site, ad three senior Health Physics technicians and one Health Physicist on site.
1 8)
From recent inspections it was noted that during normal operations the Health Physicist and Reactor Supervisor's roles are filled by one individual. Will this also be the case during the decommissioning?
If no, please state who is responsible for each of these functions.
If yes, state how you expect one individual to fill both roles.
In the period when the reactor was operational, the Reactor Supervisor was Mr. George Cozens and the Facility Health Physicist was Mr. Joe Woods. During decommissioning, with reactor operations ceased, Mr. Cozens is the Radiation Safety Officer and Mr. Woods performs the health physics function under Mr. Cozens supervision.
9)
Have you given any thought to increasing the frequency at which the vari ous committ e e s (i.e., Corporate Radiation Committee and Decommissioning Committee) will meet during the decommissioning operation. The plan currently states that the committees will meet at least quarterly; however, this might not be enough considering the fact that the decommissioning is expected to last only 6-8 months.
Yes, we have.
During the rather brief period of concentrated decommissioning activity, the Corporate Radiation Committee will meet monthly to review progress and offer guidance. For the past 2 months and throughout the decommissioning project, the Decommissioning Team has been and will continue to meet weekly.
10)
If the f acility's installed ventilation system is contaminated, what does Northrop plan to do with it?
If the facility's ventilation system is f ound to be contaminated, Northrop will either decontaminate it to acceptable levels if possible, or remove it and dispose of it as radioactive waste.
4_
11)
The Certificate of Compliance for the fuel shipping cask (e.g., Rev 11,#5957) requires that the gaskets and seals be replaced at least every 12 months or earlier if visible degradation occurs. Has Northrop verified that the 12-month replacement criteria will not be exceeded during the time that the cask remains at Northrop? Does Northrop have a supply of spare gaskets for replacement if necessary?
The BMI-1 cask was recently serviced by BCL who will supply certification of the f act. Verification of all applicable inspection / maintenance items will be made by the contractor at the time the BMI-1 cask is picked up, and will be re-verified by Northrop upon its arrival at the f acility. In addition, a service kit containing critical maintenance parts will be supplied with the cask.
12)
Since all liquid effluents from the facility are normally collected in a sump prior to discharging to the normal sewer system, does Northrop plan to perform any additional types of surveys of the sump, such as direct radiation measurements, contamination surveys, etc.?
Yes.
In addition to routine surveying and wipe tests, samples of water, sediment (sludge), and wall scrapings will be collected and sent to an independent certified lab for isotopic analysis.
13)
Section 2.3 (page 17) of the plan states that detailed work procedures written f or significant operations will be used for performing major tasks.
It is not clear who will develop the procedures or whether Northrop's staf f will review and approve all procedures prepared by the contractor.
After being written by the contractor these procedures will be reviewed and approved by the contractor's Radiation Safety Review Board and the Quality Assurance Organization.
These procedures will then be reviewed for approval by Northrop's Decommissioning Committee prior to making them operational.
e 14)
Part 2.1, Page 17, ' Surveys and Reporting", states that Health Physics will also be responsible f or assuring all personnel working in the radiation area are properly clothed and badged, and a complete record of personnel exposure is maintained. Does this include a
' determination of a worker's prior dose in accordance with 10 CFR 20.102?
Yes. Every worker's dose prior to the decommissioning project has been determined in accordance with 10CFR21.102.
15)
Please clarify whether Northrop or the contractor will be responsible for assuring compliance with DDT requirements?
Northrop will be responsible for assuring compliance with DDT requirements.
16)
Table III, " Acceptable Surf ace Contamination Levels," is not consistent wi h Regulatory Guide 1.86 in that it omits Sr-90 from beta-gamma emitters. Was there a specific reason for this omission?
Table I.. in the Northrop Decommissioning plan is essentially identical to Table I of Regulatory Guide 1.86.
In both, Sr-90 is omitted f rom the typical beta-gamma emitters (fourth group listed), but i_s included with the third group, which includes Th-nat, Th-232, Ra223, Ra224, U-232, I-126, I-131, and I-133.
17)
When you submit your final radiation survey of the dismantled and decommissioned f acility, please provide building plans of the facility, including drain lines.and other lines that still exist below grade.
Northrop will provide the requested drawings.
18)
What controls will exist to assure that rubble containing radioactive material (e.g., concrete with activation products) is properly disposed of?
Rubble containing radioactive material will be monitored, packaged, labeled and documented at the reactor site according to applicable Federal Regulations.
These packages will be shipped via the contractor's vehicle (s) to an approved dumpsite whose procedures have been reviewed and verified by Northrop.
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I trust we've been responsive.
Sincerely yours,
. Benveniste, NRTC Chief Scientist and Chairman Corporate Radiation Commmittee 1
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