ML051450517

Branch 6, Management Directive 8.3 Check Sheet for 3/15/04 Millstone Unit 2 Turbine Trip

ML051450517
Person / Time
Site:	Millstone
Issue date:	05/20/2005
From:	- No Known Affiliation
To:	Office of Nuclear Reactor Regulation
References
FOIA/PA-2005-0208
Download: ML051450517 (2)

Text

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BRANCH 6 MANAGEMENT DIRECTIVE 8.3 CHECK SHEET FOR 3/15/04 MILLSTONE UNIT 2 TURBINE TRIP NOTE: This a Record of Decision to Not Recommend a Team Inspection

Purpose:

The purpose of this record Is to briefly state the key elements of the decision made In the application of MD8.3 to events, where a team Inspection would not be Initiated.

Overview: For significant operational power Reactor events, MD8.3 calls for the evaluation of eight deterministic criteria (a through h) and If any of these criterion are met then the MD8.3 risk table Is used to aid Indetermining the level of response I.e. no additional Insp., SIT, AIT, or IIT)

Process: 1)If none of the deterministic criteria were met, those criterion that were the principal areas of discussion should Include key points of discussion In the Remarks.

2) Briefly Indicate If one or more deterministic criterion were met and:

a) Ifthe risk was exclusively In the no additional Inspection' region of the risk table, list the risk number In the Risk section below, or b) If the risk fell In the overlapping region for no additional Inspection & Special Inspection' Indicate the basis for no additional Inspection In the Risk section.

Event: Millstone Unit 2 Turbine Trip

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Criterion Y/N Remarks a N b N c N d N e N Note that turbine vibrations were normal following the reactor trip.

f1 N During this event, two S/G safety relief valves opened which constitute an unexpected response. The licensee has Investigated and determined that the steam dump valves and the atmospheric reliefs operated as designed. The licensee concluded that the safeties lifted within their set point range and consider the safety valves to be operable. The licensee has documented this trend of SIG safety valves lifting following relatively benign transients Into their CR process for evaluation and corrective action as appropriate.

However, there Is no current evidence to suggest that the lifting of these safety valves Is outside of their design basis or that this condition Impacts their safety analysis. It Is recommended that the residents follow the licensee progress as they Investigate the lifts.

0 N Although the reactor trip on March 6 and the reactor trip on March 15 were both Initiated by loss of the ABE SGFP, the licensee has determined that the reason for the loss of the SGFP In each case was unrelated and thus Is not considered a repetitive failure.

h Y On the March 15 reactor trip, operators were able to reset the SGFP but S/G level decreased to the automatic reactor trip set point before operator action was effective. After the March 6 reactor trip and this event, we engaged the licensee concerning expected operator action during a loss of a SGFP. This does not merit a special Inspection because more recent licensee Investigation has determined that It Is unlikely the operator would have been able to restore the SGFP to operation prior to SGWL reaching the automatic reactor trip setpolnt. As a result, the licensee has recently changed their Alarm Response Procedure to trip the reactor on a loss of SGFP above 70% reactor power.

RISK: CCDP was calculated by the Region I, DRS SRA to be 7 exp - 6.

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