ML020880177
| ML020880177 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 03/19/2002 |
| From: | Newberry S Office of Nuclear Reactor Regulation |
| To: | Quay T Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2001-0256 | |
| Download: ML020880177 (2) | |
Text
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Note to:T Quay
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)1 &y From: Scott wberry The attached not as received by me in an addressee only envelope on September 27, 2000.
I have no informatio on background or the author of the note.
As the current Leader o e IP2 Steam Generator Lessons Learned Task Group, I can imagine that the author made a con ection with the documented concerns and my responsibilites.
However, since our efforts ar focused only on steam generator tube integrity issues, there is nothing here that directly relates my Charter.
Please let m onow if I can be of assi nce.
Scott Newberry I
IP2 Questions:
- 1.
How reasonable are the IP2 risk calculations? - The first event discovered latent failures that were not picked up during surveillance testing or maintenance. Also, first trip was "spurious," it was only "luck" that that trip occurred before the tube rupture event occurred. (There was no other reactor trip in between those two events.) Had the latent failures in the plant on August 15, 1999 not been corrected, then it is probable that the manual trip in response to the SGTR would have triggered a LOOP and the lockout of one EDG for the same "mechanistic" reasons, making the SGTR event much more difficult to control.
- 2.
Will grid deregulation lead to more events where LOOPs are caused by reactor trips?
Plant under-voltage settings are determined based on expected grid response following certain known contingencies. In a deregulated environment, how can we assure proper coordination of plant under-voltage protection when power generation and grid operation are no longer under the control of the reactor licensee. Reactor plant operators, who no longer control how the grid is run, may not have the'information available or the grid calculational model to know if they are running in a condition which would result in LOOP given trip. And even if they did, they may not have the authority to get the grid operator to make the necessary adjustments to compensate.
- 3.
Were the AIT charters on IP2 events too limited? --Although the LOOP was the result of a voltage dip following the reactor trip and may be an indicator of generic concerns about grid voltage behavior, no data on the voltage levels was collected. Current risk calculations do not consider increased likelihood of LOOP due to reactor trip. The focus on the tap changer diverted the investigation from the more real safety concern - that plants may be subject to more severe voltage drops following a trip than was the case before deregulation.
- 4.
Is the revised reactor oversight process faulty with it's focus on a single event? - Isn't it a better indicator of the overall plant performance to include some recent past history? A "good performer" would be much less likely to have two events in a row that had significance. IP2 may be one of the worst "combination" of events ever. It wouldn't be a major effort to look back on previous trip or two at a plant involved in a potentially serious event.