ML20248G109
| ML20248G109 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/28/1989 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1636, NUDOCS 8910100083 | |
| Download: ML20248G109 (4) | |
Text
_ _ -
~-
4 4
TOLEDO EDISON A Centemr Energy Compsiy DONAU) C. SHELTON Vce Presdent-Nudear Docket Number 50-346 License Number NPF-3 Serial' Number 1636 September 28, 1989 United States Nuclear Regulatory Commission Document Control Desk Vashington, D. C.
20555 Subj ect: Revision To Davis-Besse Nuclear Power Station, Unit Number 1 Locked Valve Program Gentlemen:
The purpose of this letter is to advise the Nuclear Regulatory Commirision (NRC) of Toledo Edison's revision to the Davis-Besse Nuclear Power Station (DBNPS), Unit Number 1 Locked Valve Program. As a result of industry events, including DBNPS - specific incidents, Toledo Edison (TE) committed to lock various valves to prevent inadvertent mispositioning. Davis-Besse Faclear Power Station's resulting locked valve program has experienced several deviations, including those reported in Licensee Event Reports 81-062-,82-010, 82-017, and 82-032. A Potential Condition Adverse to Quality Report (PCA0R Number 87-0384) was generated as a result of DBNPS Quality Assurance audit findings that the Locked Valve Program was not being implemented 11 surveillance procedures or on drawings in a timely and consistent enanner.
This PCA0R was elevated to a Management Corrective Action Report (MCAR) to ensure a comprehensive resolution of the reported deficiencies to the Locked Valve Program.
Evaluation of the large nuaber of valves (approximately 400) in the Locked Valve Program and investigation as to the reasoning for their desi gnation as locked valves resulted in a reassessment of the criteria for selection of valves to be locked. The criteria to more clearly reflect the ba!,is for designation of valves to be included in the Locked Valve Program have been developed. These criteria are included in Attachment 1.
It is noted that further revision to the criteria may result as experience progresnes.
Therefore, the criteria, except for the specific (asterisked) values in I
Criterion 5, are considered illustrative rather th n binding as a commitment.
l (The asterisked valves of Criterion 5 vill require further notification of NRC if their locked status is revised.) Based on the development of m locked valve selection criteria, commitments made previously regarding tiae locking of valves, except as previously cited, are herewith superseded.
g ikl l
THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDD, OHIO 43652 8910100083 890928 PDR ADOCK 05000346 P
FDC
,_ fji
',' f s
n, v
jig:7 4 }'DockstNunbar".50-346"
!:3t
, JLicense; Number-NPF-3.L Serial Number-1636' MI'
-Page.2-b.
lIf you have any; questions concerning this matter,;please contact Mr. R. V..Schrauder,' Nuclear Licensing Manager, at (419)_249-2366.-
Very trulyc urs,-
E
?RMC/ dim g
cc:.P.;M. Byron,'DB-liNRC Resident Inspector
'A. B. Davis',-~ Regional Administrator, NRC Region III sT. V. VambachiDB-1 NRC Senior Project Manager a
b
=
9 l.
I>
i 4
I ' ',
,Dscket Numb r,50-346' l
C Licensa Number NPF-3'
.1 Serial Number 1636 l
Page'1 Davis-Besse Nuclear Power Station Locked Valve Criteria In general, a valve'shall be considered for locking if its position is essential in supporting "the intended" safety function of the system in which it is installed or.to fulfill a design code or regulation. Additionally, the l<
valve must be located in a stand-by system such that mispositioning of the valve vould not be detected during normal plant operation.
For the ease of j
the application of these two conditions, the following' criteria have been developed.
Criterion 1 Valves in the Core Flood (CF), Emergency Ventilation System (EVS), Emergency Diesel Generator -(EDG), High Pressure Injection (HPI), Low Pressure Injection (LPI), Containment Spray (CS), and Auxiliary Feedvater (AFV) systems are to be locked if they fulfill any of the following functions:
A.
. Ensure the post accident system flow path is immediately available to mitigate the consequences of an accident / transient.
B.
Preclude the significant loss of inventory or flow path diversion, (i.e.,
for any branch line which is larger than 1/3 the diameter of the system flov' path).
C.
Ensure support equipment or systems are immediately available to provide adequate seal water, cooling water, lubrication and or minimum recirculation protection including fuel / air requirements. This requirement only applies to valves in the support system's branch connections that are not in service during normal plant operation (e.g.,
component cooling vater (CCV) to diesel cooling water jacket).
Exceptions to the above criterion are permitted provided that one of the following valve design considerations is met:
1.
Valve receives an automatic actuation signal and valve meets response time criteria for the system to allow the system to perform its safety function with the valve initially out of its normal position.
2.
Valve is remotely operated aad there is a control room annunciator vindow when the valve is in the unsafe position.
Criterion 2 Valves shall be locked and controlled when isolation valves are in an overpressure protection relief flow path required by applicable ASME codes.
Criterion 3 Containment isolation valves shall be locked as required by the General Design' Criteria of 10CFR50 Appendix A.
Docket Numbsr'50-346 i
- ' h ~Licenss1Numbsr'NPF-3
{
. Serial Number'1636-Page 2 Criterion 4 Valves required'to be locked as specified in the Technical Specifications-shall be locked.
Criterion 5 Although the following valves do not meet criteria 1 through 4, these valves are controlled under locked valve program for reasons specified below.
MS5889A handwheel & MS5889B handwheel - The handwheels for these valves are locked in a position as not to impair valve movement to support Auxiliary-Feedwater System operation.
MU190, MU191, MU203, MU206, & MU479 - These valves support minimum recirculation flow path for makeup pumps.
- DH14A handwheel and DH14B handwheel - The handwheels for these valves are locked to prevent mispositioning due to lack of redundant position indication when power is removed from these valves' actuators.
SV86, SV94, SV102, SW108, SV116, SV371, SV381, CC659, CC662, CC652, CC655 -
l These valves are locked closed to prevent reverse flow through system check valves in lieu of testing.
E
- CD163 and CD164 - These valves are locked open to cross connect the Condensate Storage Tanks (CSTs) so that the CSTs, in effect, function as single tank and the single level indictors and alarms on each tank provide required redundancy.
- DH21 and DH23 - These valves are locked closed during Modes 1 through 4 (when isolation of the Decay Heat Removal System is required) using a unique key and lock to satisfy License Condition 2.C.(3)(p) (License Amendment Number 29 dated August 11, 1980).
- Note: Changes to the locked status of these valves or handwheels will require notification and, as applicable, approval of NRC.