ML20009F857
| ML20009F857 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Crane |
| Issue date: | 07/01/1981 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | AFFILIATION NOT ASSIGNED |
| Shared Package | |
| ML20009F855 | List: |
| References | |
| TASK-81-16, TASK-GL GL-81-16, NUDOCS 8108030106 | |
| Download: ML20009F857 (2) | |
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NUCLEAR REGULATORY COMMISSION 5
E WASHINGTO N. D. C. 20555 July 1, 1981 ALL LICENSEES OF OPERATING PLANTS AND HOLDERS OF CONSTRUCTION PERMITS Gentlemen:
SUBJECT:
STEAM GENERATOR OVERFILL (GENERIC LETTER 81-16)
In a letter dated March 28, 1980 from H.R. Denton, we informed you of the revised criteria to be used by the staff in evaluating reactor operator training and licensing that could be implemented under the current regulations. We also advised you that Comission review in the area of operator training and qualification was continuing and it could be expected to result in additional criteria.
The NRC Office of Aiialysis and Evaluation of Operational Data has produced a report entitled, "AEOD Observations and Recomendations Concerning the Problem of Steam Generator Overfill and Combined Primary and Secondary Side Blowdown," dated December 17, 1980, a copy of the report is enclosed.
This report documents results of studies completed to date by the Office of Analysis and Evaluation of Operatior.al Data with regard to the steam generator overfill problem.
This report expresses concerns in the following area:
(1) increased dead weight and potential seismic loads placed on the main steamline and its support should this line become flooded; (2) the load placed on the main steamlines due to the potential for rapid collapse of steam voids resulting in water hamer; (3) the potential for secondary safety valves sticking open following discharge of water or two-phase flow; (4) the potential for rupture for weakend tubes in the once-through-steam-generator (OTSG) on B&W NSSS plants due to tensile load' caused by the rapid thermal shrinkage of the tubes relative to the gaerator shell.
From the examining experiences of the Operator Licensing Branch, operators at nuclear power plants are aware of the nedd to avoid overfilling steam generators and not operating steam systems.with water _ accum.ulation.
Howev~er! thdre ~msy be~a'ieneral lack ~of acordciation of the ootential
. seriousness of situations that can arise from these events.
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While this issue is being studied further, we request that you determine which scenarios are credible for your plant and that you include in your oyfrall trainina program, plant-specific information Stressino the
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imoortance of feedwater flow as well a.; the possible consecuences of steam cenerator overfill.
This information should be factored into your initial operator training programs and the operator req'ualification programs.
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