ML20027B311
| ML20027B311 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/16/1982 |
| From: | Kanga B GENERAL PUBLIC UTILITIES CORP. |
| To: | Barrett L Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20027B312 | List: |
| References | |
| 4410-82-L-0006, 4410-82-L-6, NUDOCS 8209200262 | |
| Download: ML20027B311 (4) | |
Text
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GPU Nuclear g{
P.O. Box 480 Middletowri, Pennsylvania 17057 717-944-7621 Writer's Direct Dial Number.
September 16, 1982 4410-82-L-0006 TMI Program Office Attn: Mr. L. H. Barrett, Deputy Program Director US Nuclear Regulatory Comnission c/o Three Mile Island Nuclear Station Middletown, PA 17057-0191
Dear Sir:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating License No. DPR-73 Docket No. 50-320 Recovery Operations Plan Change Request No. 18 Equipment Hatch Personnel Airlocks The attached Recovery Operations Plan Change Request is submitted for your approval to permit the simultaneous opening of both personnel airlock doors in the equipment hatch. This request is submitted to allow the passage of certain excessive length tools and equipment into the containment. Due to the excessive length of the equipment, it is not possible to use Personnel Airlock No. 2 for the passage of the equipment.
The capability to open both equipment hatch airlock doors will greatly 9g/
o facilitate the decontamination of the Reactor Building and the re-furbishment of the polar crane.
Sincerel,
W q.
n m
g B. K. Kanga 8
Director, TMI-2 y
BKK/RBS/jep i5 EE B[P Attachment E
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CC: Dr. B. J. Snyder, Program Director - IMI Program Office 3
g ro 8209200262 820916 DR ADOCK 05000320 PDR is a part of the General Public Utilities System
Wree Mi19 Islud Nuclear Stetion, Unit 2 GMI-2)
Operating License No. DPR-73 Docket No. 50-320 1.
Recovery Opertions Plan Change Request No. 18 3e licensee requests that the attached page (4.6-1) of the 'IMI Recovery Operations Plan (ROP) replace the existing Recovery Operations Plan page 4.6-1.
II. Reason for Change
'Ihis change is requested to support the movement of extra long pieces of equipment into the contaiment building. %e equipment consists of four 30 foot long sections of scaffolding to be used in the decontaination of the Reactor Building dane and for the decontamination and refurbishnent of the Polar Crane. De refurbishnent of the Polar Crane is considered essential for the continued cleanup of the Reactor Building. After refurbishnent of the Polar Crane, the scaffolding will be utilized in other phases of the cleanup operation. % e scaffolding's excessive length prohibits the usage of the Personnel Airlock No. 2 doors for noving the scaffolding into contaiment. Although not specifically defined, there could be other evolutions which would require the opening of both airlock doors.
III. Safety Evaluation Justifying Change Technical Specification 3.6.1.3 pemits both doors of a containment airlock to be open sinultaneously when necessary to permit the passage of tools and equipment. Procedures apyroved pursuant to Technical Specification 6.8.2 are required for operations wnich require that both airlock doors be open sinultaneously.
Procedures will ensure that there will be no significant releases of radioactivity while both airlock doors are open. %e contaiment purge exhaust will be operated when both airlock doors are open. This induces a nominal airflow of between 300 and 1400 feet per minute into containment through the open airlock. 'Ihis airflow is based on a contaiment purge exhaust flow of between Sp00 and 25,000 cfm. 'Ihis inward airflow will help to ensure that airborne radioactivity will renain in the contaiment.
When the airlock doors are opened, there may be a small release of radioactivity to the environment frm the airlock volme due to the fact that the contaiment purge exhaust fan is shut off to equalize contaiment pressure. When the inner airlock door is opened, the contaiment purge exhaust will be reestablished inmediately. Connunication will be maintained between the Comand Center and the airlock throughout opening operations and while both airlock doors are open. The release during this period has been conservatively calculated based on past contaiment airborne concentrations (first quarter of 1982) to be 0.3 microcuries of cesim-137, 0.03 microcuries of cesim-134, 0.2 microcuries of strontim-90, and 30.5 microcuries of trititrn. Using annual average site meteorology, the release concentrations at the site boundary will be 2 x 10-13 microcuries/ml of cesitzn-137, 2 x 10-14 microcuries/ml of cesium-134,1.4 x 10-13 microcuries/ml of strontitzn-90, and 2 x 10-11 micro-curies /ml of tritium. %ese releases are based on the total voltrae of air in the airlock being released in 10 seconds. %ese concentrations are well within the limits of the Technical Specifications. Doses associated with these releases are bounded by the calculations discussed below.
l A bounding analysis was perfomed to quantify the release of radioactive material and determine the offsite raciological consequences of any credible accident. Tsing the contaiment airborne concentrations from the first quarter of 1982, the quantity of airborne radioactive material in the l
contaiment was estimated to be 8.92 x 10-4 Ci of cesim-137, 8.92 x 10-5 Ci of cesium-134, 5.95 x 10-4 Ci of stronti m-90, and 0.089 Ci of tritim. The analysis assmed that the contaiment purge exhaust system failed and the entire quantity of airborne radioacti.ve material in the contaiment is released to the environment through the open persomel airlock over a time period. of 30 minutes. This scenario is not considered credible but is presented here to bound any credible event. Using the atmospheric dispersion parameter from the Offsite Dose Calculation Manual for a ground level release the inhalation dose at the nearest residence was determined to be:
Organ Dose (mrem)
Total Body 0.36 x 10-2 Bone 0.53 x 10-1 Lung 0.82 x 10-2 Liver 0.7 x 10-3 The limiting age group was the teenage group. Considering the extreme unlikelihood of releasing the entire quantity of airborne radioactivity through the airlock over the 30 minute time, and the resulting sna11 dose, the results of the analysis are considered acceptable.
The analysis is considered bounding for the following reasons. Procedures will require that contaiment integrity be reestablished whenever the contaiment purge exhaust system fails. The 30 minutes to close an airlock door will allow sufficient time to remove any materials being transported in o or out of contaiment that may be preventing the closure of an airlock Joor. The release of the entire quantity of airborne radioactivity in the contaiment will envelop any release due to a credible event hacama no credible event would result in releas all the airborne radioactivity and there are only a few ways to increase concentration of airborne contamination in the contaiment and increase the release. The credible event that could cause the greatest increase in airborne containation is a fire in the contaiment in which containated surfaces, for exanple, cables and coatings, are involved. Fires involving materials of this type are slow developing and would not contribute significantly to the concentration of airborne contamination in the contaiment over the short period of time required to close one of the airlock doors. In addition, during periods of time when the airlock doors are both open, activities that could cause a fire will be minimized, thereby minimizing any potential for a release of radioactivity greater than that assmed in the analysis.
Additionally, the following measures will be taken during the period when both airlock doors are open to help minim 4w any releases to the enviroment:
1.
When both airlock doors are open there will be at least one person in the inmediate vicinity of the airlock at all times 2.
Cannunications will be maintaine'd between the airlock and the em =vnd Center.
3.
h contaiment and all activities will be under monitor from the Comand Center.
4.
'Ihe contaiment exhaust fans will be operating
~
at all times (except when necessary to shut off to equalize pressure).
5.
An alarming radiation monitor and tritite bubbler will be in the inmediate vicinity of the airlock.
The particulate detector will be adjusted to alarm
_ if airborne concentrations exceed a predetermined value above background. The alarm will help to ensure a quick response (door closure) should a situation arise where there is a significant release of particulate to the atmosphere.
The combination of these factors coupled with the ability to rapidly close the airloc2 doors will minimize any potential release of radioactive material to the environment resulting from any credible accident when both airlock doors are open.
Based on the above, having both doors of Airlock No. 1 open at the same time can take place without endangering the health and safety of the public.
L e
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