ML20150C838
| ML20150C838 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/11/1988 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20127A683 | List:
|
| References | |
| NUDOCS 8803220339 | |
| Download: ML20150C838 (2) | |
Text
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"j NUCLEAR REGULATORY COMMISSION 5
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SAFETY EVALUATION REPORT BY THE OFFICE OF SPECIAL PROJECTS EMPLOYEE CONCERN ELEMENT REPORT 22902 "RADI0 ACTIVE PANEL DRAINS TO FLOOR DRAINS" TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 1.0 SUBJECT Category:
Construction (10000)
Subcategory:
Damage Construction Control (15100)
Element:
Instrument and Control Design, Radioactive Panel Drains into Floor Drains (22902)
Employee Concerns:
XX-85-127-001, IN-85-143-003, IN-85-197-002, IN-85-514-002, IN-85-748-001, IN-85-952-001, IN-85-983-001 2.0
SUMMARY
OF ISSUE There is a potential for liquid ard airborne radioactive contamination spread as a result of drains from instrr. ment panels or sampling sinks that receive inventory from sources having a reasonable potential for carrying radioactive materials routed to open floor drains rather than to closed equipment drains.
The presumed release path within the plant would arise from venting of gases or backflow of licuids through the open drain fixtures embedded in the concrete floor.
The offsite release path postulated by one concern would be via a presumed conventional sewage / storm drainage path as is the case with plumbing of this type in a comercial building designed to the Uniform Plumbing Code.
3.0. EVALUATION The employee concerns, namely, radioactive material disposed into open drain systems, were deternined to be valid.
TVA and their consultant, Bechtel i
Corporation, identified a total of 9 panel instrument drains in the Reactor Building Units 1 and 2 through their walkdown inspections.
These panel drains are routed to headers that connect to open floor drains.
The possibility of j
draining of radioactive material onto the floor does exist.
- However, connection of panel drains to open floor drains through the header is e.n acceptable practice provided that a consideration is given in the design to limit personnel exposure and release of untreated radioactive material to the environment, kh No$
e P
. The quantity of radioactive materials associated with these identified panel instruments drains (usually 1/2-to 3/8-inch stainless steel tubings) were found to be small and the liquid temperature is below the boiling point.
These factors minimize exposure to personnel.
During power operation, entrance is permitted in the reactor buildings only with strict health physics controls.
Radioactive materials should not be released to the environment because the radioactive contaminated drain systems terminate either at the Waste Holding Tank or are pumped to the Floor Drain Collector Tank where the liquid is sampled to establish the treatment requirement prior to release or recycling.
No contaminated drainage is released to the environment without proper monitoring.
Based on the reasons stated above, the staff concurs with licensee's conclusions that potential radioactive inventory will not be released without proper monitoring and treatment and potential exposure of operating personnel is within regulatory guidelines.
Therefore, the concern, while correctly stated, does not warrant corrective action.
4.0 CONCLUSION
Based on the discussions above, the staff concludes that the licensee's resolution precedure of the open drain issue is coraprehensive and their reco mandation of no corrective action is acceptabic.
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