ML050840517
| ML050840517 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 04/11/2004 |
| From: | - No Known Affiliation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2004-0282 | |
| Download: ML050840517 (2) | |
Text
I 1amTrack Reports Page 43 of 60 NMC > Sites > Point Beach - Action Request > Corrective Actn Program (CAP) AR Section 1 Activity Request Id:
Activity Type:
f One Line
Description:
t Detailed
Description:
CAP055585 CAP Submit Date:
4/11/2004 23:26:05 Improvement to Hot Leg Vent Path Controls Required.
4/1112004 23:26:05-OMILLIAN, MICHAEL:
Three CAPs have been written discussing various issues relating to the sequencing of hot leg vent path work during U1R28. The CAPs are CAP055576, CAP055547, and CAP055548.
CAP055576 deals with the sequencing of Steam Generator Manway removal. CAP055547 deal with the Installation of nozzle dams and vent path requirements. CAP055548 deals with the removal of all but four manway bolts prior to reduced inventory (i.e. system intact).
These issues are significant due to Reactor Coolant Inventory being at a reduced inventory volume with the potential for a loss of decay heat removal (DHR). As a result, if a loss of DHR were to occur the core would boil causing the upper vessel pressure to increase. If a hot leg vent path of sufficient size does not exist to relieve vessel pressure the potential for vessel inventory loss exists if a cold leg vent path is open. Therefore it is critical that the station understands the concern and adequate controls are in place to prevent the potential for the expulsion of water through a cold leg vent.
As indicated in both CAPs above the controls in place appear to be controlled via the outage schedule. OP-4F, 'Reactor Coolant System Reduced Inventory Requirements," does include some information on the vent path requirements but the conditions are reviewed as an initial condition prior to entry into reduced inventory. As a result the potential exist for the creation of a cold leg opening after reduced inventory is entered.
As a result if the cold leg pressurizer manways are inadvertently removed first a cold leg vent path of suffiecent size would exists to allow rapid blowdown of vessel inventory as a result of a loss of DHR. Therefore a sufficient hot leg vent path is always required to be open to prevent the potential loss of Inventory due to the pressurization of the upper reactor vessel.
Previous Industry events have required that stations evaluate their reduced inventory controls and procedures to prevent the possibility of such events per GL 88-17, which PBNP did perform.
However it appears that we currently are using the outage schedule to ensure the hot leg vent path requirements are met. As a result individuals not knowledgeable with the reduced Inventory requirements may not have the information available to understand the need for a hot leg vent path.
As a result of these issues It appears an evaluation of the stations reduced inventory process and procedures is required to ensure that adequate procedural controls exists to properly control a hot leg vent path. In addition NP 10.3.6 'Outage safety Review and Safety Assessment should be revised to discuss the critical evolution of reduced inventory, the hot leg vent path requirements, and reference GL 88-17.
4111/2004 23:42:13 - HASTINGS, MARTIN:
Correction: Fourth paragraph should read 'As a result if the cold leg Steam Generator manways are inadvertently removed first......
Initiator:
- OMILLIAN, MICHAEL
-J Initiator Department:
Date/Time of Discovery: 4/11/2004 23:11:42 Date/Time of Occurrence:
EESN Engineering Equipment Systems NSSS Mech PB V 4/11/2004 23:11:42 (None)
(None)
(None)
Identified By:
Equipment # (1st):
Equipment# (2nd):
Equipment U (3rd):
Site/Unit:
Why did this occur?:
Site-identified (None)
(None)
(None)
Point Beach - Unit 1 System:
Equipment Type (1st):
Equipment Type (2nd):
Equipment Type (3rd):
(None)
I'T'*q 4/11/2004 23:26:05 - OMILLIAN, MICHAEL:
Schedule controls are utilized to ensure proper sequencing of hot leg vent path activities.
.http://enwvs02/tmtrack/tmtmck.dll?ReportPage&Template~reports%2Frptexec&Reportld=55 4/12/2004
I TeamTrack Reports Page 44 of 60 There may be a lack of knowledge on hot leg vent path requirements since outage requirements are not described in the FSAR but have been guided and driven by industry events.
immediate Action Taken: 4/111/2004 23:26:05 - OMILLIAN, MICHAEL:
None Recommendations:
4/11/2004 23:26:05 - OMILLIAN, MICHAEL:
Perform a multi-disciplined evaluation of the stations outage process and procedures to ensure that adequate procedural controls exists to properly control a hot leg vent path.
NP 10.3.6 'Outage safety Review and Safety Assessment," document owner to revise the procedure and discuss the critical evolution of reduced inventory, the hot leg vent path requirements, and reference GL 88-17.
f> Notify Me During Eval?: Y d SRO Review Required?:
Section 2 Operability Status:
Basis for Operability:
e Unplanned TSAC Entry:
NA 6 Compensatory Actions:
N 411112004 23:42:13 - HASTINGS, MARTIN:
No specific equipment operability is being questioned. Initiator is documenting site weakness in the area of hot leg vent path control.
N v External Notification:
N http:H/enwsO2/tmtrackltmtrack.dll?ReportPage&Template=reports%2Frptexec&Reportld=55 4/12/2004
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