ML052100415
| ML052100415 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/20/2005 |
| From: | Blough A, Lanning W Division Reactor Projects I, Division of Reactor Safety I |
| To: | Barber G, Marvin Sykes Division Reactor Projects I |
| References | |
| FOIA/PA-2005-0208 | |
| Download: ML052100415 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 20, 2005 MEMORANDUM TO:
Marvin D. Sykes, Manager Special Team Inspection G. Scott Barber, Leader Special Team Inspection FROM:
Wayne D. Lanning, Director Division of Reactor Safety
/RAI
/RA/
A. Randolph Blough, Director Division of Reactor Projects
SUBJECT:
SPECIAL TEAM INSPECTION CHARTER -
MILLSTONE UNIT 3 NUCLEAR GENERATING STATION A special Inspection has been established to inspect and assess an event that occurred on April 17, 2005, at the Millstone Unit 3 Nuclear Generating Station. At 8:29 a.m., Unit 3 experienced an automatic trip from full power. In addition to the Reactor trip, one of two safety Injection (SI) and main steam isolation (MSI) subsystems actuated. Multiple main steam safety valves (MSSV) lifted and at least one MSSV appeared to remain open. Failure of the MSSV to reclose resulted in the declaration of an Alert at 8:42 a.m.
Unexpected equipment responses during the event included the trip of a turbine-driven auxlliari-feedwater pump on startup; overfill of the pressurizer as a result of the SI actuation; relief of reactor coolant system inventory to the pressurizer relief tank (PRT) through either a primary system safety valve (PSSV) or a pilot operated relief valve (PORV); indication of continued leakage past a pressurizer PORV; and charging system packing leakage resulting in local contamination in the auxiliary building. The special Inspection will commence on or about April 20, 2005, and will Include:
Manager:
Marvin D. Sykes Chief, Performance Evaluation Branch Leader:
-G. Scott Barbell Senior Project Engineer Full Time Members:
Part Time Members:
Thomas Sicola; Reactor Inspector Donald Jackson, Senior Project Engineer Joseph Schoppy Senior Reactor Inspector Wayne Schmid,, 'Senior Risk Analyst Ronald Nimltz -Senior Reactor Inspector Nicole Siellerpleactor Inspector
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 2
- jwi special team inspection was initiated in accordance with NRC Management Directive 8.3, "NRC Incident Investigation Program." The decision to perform this special team inspection was based on deterministic criteria in Management Directive 8.3 and the initial risk assessment.
The inspection will be performed in accordance with the guidance of NRC Inspection Procedure 93812, "Special Inspection," and the inspection report will be issued within 45 days following the exit meeting for the inspection. If you have any questions regarding the objectives of the attached charter, please contact Wayne Lanning at 610-337-5126.
Attachment:
Special Inspection Charter
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205550001 3
Distribution:
S. Collins, RA J. Wiggins, DRA R. Blough, DRP W. Lanning, DRS B. Holian, DRP J. Monniger, DRS V. Nerses, PM, NRR G. Miller, NRR G. Wunder, NRR J. Kramer, NRR P. Krohn, DRP S. Schneider, DRP K. Jenison, DRP W. Cook, DRS W. Schmidt, DRS D. Scrend, ORA Region I Docket Room (with concurrences)
DOCUMENT NAME: C:Vemp\\Mfillstone SIT Charter 4_17_05 Event RevO.wpd SISP Review Complete:
MDS (Reviewer's Initials)
After declaring this document "An Official Agency Record" it will not be released to the Public.
To receive a copy of this document, Indicate In the box: OC = Copy without attachmentlenclosure "E = Copy with attachmentlenclosure N" = No copy OFFICE RI/DRP E RI/DRP
[RI/DRS
[ RIIDRP Rl/DRS NAME iSBarber.
=PKrohn nMSnkes
_ning DATE
[04119/05 04/19/05 04/19/05 04/19/05 04/20/05 Official Record Copy
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205550001 Special Inspection Charter Millstone Nuclear Generating Station Unit 3 Reactor Trip and Safety Inlection With Failure of Main Steam Safety Valve to Reseat Preliminary information regarding the event: On April 17, 2005, at 8:29 a.m. Millstone Unit 3 experienced a reactor trip from full power. In addition to the reactor trip, one of two trains of the Si and MSI subsystems actuated. Control room operators manually initiated a full Si and MSI.
There were also indications that multiple MSSVs opened with at least one MSSV that appeared to remain open. As a result, at 8:42 a.m., Dominion Nuclear Connecticut (DNC) declared an Alert due to the failure of at least one MSSV to reclose. The response of the MSSVs is under further review.
The SI and MSI signals were initially attributed to a sensed low steam line pressure on one of four steam generators. Auxiliary Feedwater (AFW) automatically actuated during the event.
However, the turbine-driven AFW pump initially tripped and was successfully reset locally and restarted. Both motor-driven AFW pumps operated as expected to maintain steam generator levels. Due to the additional Inventory added during the SI, the pressurizer filled and an overpressure condition caused pressurizer valves to lift. Operators responded to these conditions, stabilized the plant in H6t Standby and began a cooldown. Subsequently, the plans entered hot shutdown at 7:03 p.m. and DNC terminated the Alert at 7:05 p.m Obiectives of the Special Inspection: The objectives of the special inspection are to evaluate the circumstances associated with the event described above. Specifically, the Inspection should:
- 1.
Develop or verifvf
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IndeiendentIv determine[
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Understandr
- 4.
Independently-evaluatq SO,8J
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 2
,S-
- 7)
Evaluatd
- 8) LRevieO 7 S.
I
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Reviews
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Document the inspection findings and conclusions in a special inspection report in accordance with Inspection Procedure 93812 within 45 days of the exit meeting for the Inspection.