ML20116H653
| ML20116H653 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/09/1992 |
| From: | Myers T CENTERIOR ENERGY |
| To: | |
| Shared Package | |
| ML20116H642 | List: |
| References | |
| NUDOCS 9211130226 | |
| Download: ML20116H653 (8) | |
Text
+1 Dochet Numbar 50-346 License Numbar NPF-3 Serial Number 2084
' Enclosure Page 1 APPL.ICATION FOR AMENDMENT TO FACILITY OPERATING LICENSE NUMBER NPF-3 P
DAVIS-BESSE NUCLEAR-POVER STATION UNIT NUMBER 1 Attached are requested changes to the Davis-Besse Noclear Power Station, Unit Number 1, Facility Operating License Number NPF-3. Also included is the Safety Assessment and Significsnt Hazards Consideration.
The proposed changes submitted under cover letter Serial Number 2084 concern:
i Appendix A, Technical Specification (TS) 3/4.5.2, Emergency Core Cooling Systems - ECCS Subsystems --T 22 and3/4.5.3,~EmergencyCoreCoolingS)Nems80'F,TSBases.3/4.5.2 ECCS Subsystems, and TS Bases 3/4.6.2.1, Containment _ Systems - Depressurization and
! Cooling Systems - Containment Spray System a
Fort D. C. Shelton, View President, Nuclear - Davis-Besse l
By: [. hp T. < Hfers Di ect,4r_- DB Technical Services Svorn and Subscribed before me this 9th day of November, 1992, da4w>f. mb Notary Public, State of Ohio L
EVELYNL DRESS l.
' NOTAlV FU200. STATE OF OHO W Comm=en E'#esJuy 28,1964 l- 921123b226 921109 PDit l-P ADOCK 05000346 POR
. Docket Number 50-346
', Licenso Number NPF-3 Serl.a1 Number 2084 Enclosure Page 2 The following information is provided to support issuance of the requested changes to the Davis-Besse Nuclear Power Station, Unit Number 1, Operating License Number NPF-3, Appendix A Technical Specifications.
A. Time Required to Implement: This change is to be implemonted within 90 days after the NRC issuance of the License Amendment.
B. Reason for change (License Amendment Request 91-0002, Rl): This application requests revision to TS 3/4.5.2, Emergency Core Cooling Systems - ECCS Subsystems - T 2 280' F, TS Bases 3/4.5.2 and E
3/4.5.3, Emergency Core CoollSg Systems - ECCS Subsystems, and TS Bases 3/4.6.2.1, Containment Systems - Depressurization and Cooling Systems - Containment Spray System, to reflect the de-energization of the Borated Vater Storage Tank (BVST) outlet isolation valves DH-7A and DH-7B in the open position, during operational Modes 1, 2, 3, and 4. This vill allov for restructuring of the shift crew composition. The TS required mii.imum shift crew composition size (TS 6.2.2a) or fire brigade : Are 'TS 6.2.2f) are not affected by this amendment request. Surveillance Requirement 4.5.2.d.2.b is proposed to be revised to tr'.' lect the testing of the valves' interlocks only uuring times of energization.
The proposed change for valves DH-7A and DH-75 is similar to a TS Bases change regarding valves DH-9A and DH-9B (the containment Emergency Sump recirculation valves) accepted by the Nuclear Regulatory Commission (NRC) in its letter of October 21, 1992.
This application also adds a similt.r Bases change to TS Bases 3/4.6.2.1 (Containment Spray System) for consistency purposes.
C. Safety Assessment and Significant Hazards Consideration: See ,
attached. _
P
Docket Nunbar 50-346 1
4
. Licensa Number NPF-3 l
Serial N imber 2084 Attachment
'Page 1 SAFETY ASSESSMENT AND SIGNIFICANT HAZARDS CONSIDERATION TITLE:
Proposed Revisions to Technical Specification (TS) 3/4.5.2, Emergency Core Cooling Systems - ECCS Subsystems - T h 280* F, TS Bases 3/4.5.2and3/4.5.3,EmergencyCoreCoolinkV5ystems-ECCScbsystems, u and TS Bases 3/4.6.2.1, Containment Systems - Depressurizacion and Cooling Systems - Containment Spray System, to Reflect De-energitation of Borated Vater Storage Tank Outlet Inolation Valves DH-7A And DH-7B During Modes 1, 2, 3, and 4 DESCRIPTION:
This License Amendment Request (LAR) proposes revision of Davis-Besse Nuclear Power Station (DBNPS) Opersting License NPF-3, Appendix A, TS 3/4.5.2 TS Bases 3/4.5.2 and 3/4.5 3. and TS Bases 3/4.6.2.1 to allow the de-energization of the Borated Vater Storage Tank (B'13T) outlet isolation valves DH-7A and DH-7B, in the open position, during operational Modes 1, 2, 3, and 4. These valves vould be de-energized by opening their breakers locally at their respective Motor Control $
Centers (HCCs) prior to entry into Mode 4 during startup. The effect of these changes vill allow the restructuring of the crew composition such that one position in Toledo Edison's crew composition on each of the six shiftr can be eliminated. No change is necessary to the TS reqaired staffing of the mi.timum shift crew compositi n (TS 6.2.'a) or the fire brigade (TS 6.2.2f).
Surveillance Requirement 4.5.2.d.2.b is proposed to be revised to reflect the testing of the valves' interlocks only during times of motor operator energization.
These proposed changes for valves DH-7A and DH-7B follow a TS Bases change proposed in a letter submitted to the Nuclear Regulatory Commission (NRC) on October 4, 1990 (Toledo Edison (TE) letter Serial Number 1817), regarding valves DH-9A and DH-9B. This application also r adde the Dnses change proposed in that letter to TS Bases 3/4 n 2.1 for consistency purposes.
As a purely editorial correction, the heading to TS 3/4.5.2 on page 3/4.5-3 is proposed to have the ' greater than or equal to' sign added between the 'T avg ' and '280*F'.
SYSTEMS, COMPONENTS, AND ACTIVITIES AFFECTED:
Valves DH-7A and DH-7B (BVdT outlet isolation valves)
Valves DH-9A and DH-9B (Containment Emergency Sump recirculation valves)
(Note A simplified system drawing shoving these two sets of valves is provided at the _ id of the package.)
The interlock between valvas DH-7A/B and DH-9A/B Minimum shift crew composition activities
Docket Numbar 50-346 Licenso Number NPF-3 Serial humber 2084 i
Attachment
~Page 2 SAFETY FUNCTIONS OF THE AFFECTED 5 ETEMS, COMPONENTS AND ACTIVITIES:
During Modes 1 through 4, motor-operated 14-inch gate valves DH-7A (Train 2) and DH-7B (Train 1) allow BVST inventory to be provided to the Decay Heat Removal /Lov Pressure Injecti;n Pumps in the Low Pressure Injection mode and to the High Prersure In section System for high pressure reactor coolant System injection. They also provide inventory for the containment spray pumps.
In the event of a loss of coolant accident (LOCA), motor-operated 14-inch gate valves DH-9A (Train 2) and DH-9B (Train 1) ellow for suction from the Containment Emergency Sump once the BVSi inventory is depleted and eafficient inventory (360,000 gallons minimum per cecident analysis) exists in the Containment Emorgency Sump to provide the required net positive suction head for the Decay Heat Remmial/ Low Pressure Injectior Pumps and the Containment Spray Puw= . Velves DH-9A and DH-9B are normally closed and required to ren.ain c; ead for saf.a shutdown, from a 10 CFR Part 50, Appendix R standpoir.t, 3,
- hat BVST inventory is not diverted to the Containment Emergenty Sump (and thus making it unavailable for normal shutdown) in the event of spurious opening c f the valves. If these valves were to open, the containment Emergency Sump could also fill with BVST inventory to the point where water could come into contact with the teactor vassel and thereby cause thermal shock. To prevent spurious opening of valves OH-9A and DH-9B under 10 CFR Part 50, Appendix R considerations, their motor operators are de-energized during Modes 1, 2, 3, and 4.
Valves DH-7A and DH-7B are interlocked with valves DH-9A and DH-9B, precluding the simultaneous cpening of one or both sets of valves which could cause draining of the BVST to the Containment Emergency Sump.
Valves DH-7A and DH-7B receive Safety Yeatures Actuation System (SFAS)
Level 2 and Level 5 signals. The SFAS Level 2 signal (indicative of high containment pressure or los reactor coolant system pressure) sends an open signal to these normally open valves (as well as a close signal to normally closed valves DH-9A and DH-9B) to ensure that the BVST is available to the High Pressure Injection Pump, Lov Pressure Injection Pump and Containment Spray Pump suctions. The SFAS Level 5 signal (BVST low-low level) sends a permissive signal to valves DH-9A and DH-98, thus permitting the shifting of pump suctions to the Containment Emergency Sump. Thus, due to the interlock, valves DH-7A and DH-7B normally close when the operator opens valves DH-9A and DH-9B.
The safety function of the shift crew composition is to ensure that the plant can be safely brought to cold shutdown (Mode 5) under all conditions.
EFFECTS ON SAFETY:
During TE's previous reviev of Control Room and Cable Spreading Room fire scenarios in accordance with 10 CFR Part 50, Appendix R, it was determined that a fire in either of these areas could cause spurious closing of valves DM-7A and DH-7.B, thus isclating the BVST. This vould prevent BVST vatet from being available for use in a normal plant shutdnvn. Valves CH'7A and DH-7B are both located in Fire Area AC.
Decket Nunbar 50 346 License Number NPF-3
. Serial Number 2084 Attachment
'lage 3 The Davis-Besse Nuclear Power Station (DBNPS) Fire Hazard Analysis Report (FHAR), Revision 12, Section 4.6.AC, credits Train 2 (valve DH-7A) for safe shutdown in this fire area. FHAR Section 4.6.AC recognizes that a hot short, such as from a fire, could cause spurious closure of valve DH-7A and, therefore, requires the opening of breaker BF1148 locally at Motor Control Center (HCC) F11B to allov, if necessary, manually opening valve DH-7A by hand. Similarly, FHAR Sections 4.6.DD and 4.6.FF credit Train 1 (Valve DH-7B) for safe shutdown in these fire areas and recognizes that a hot short could cau.i .7"rious closure of valve DH-78. Similar to valve DH-7A, manual operator accion as required during a cable spreading room / control room-fire to locally open breaker BE1157 at MCC EllA and manually open valve DH-7B, if necessary.
The proposed changes vould allow the motor operators of valves DH-7A and DH-7B to be de-energized in their open positione during Modes 1, 2, 3, and 4 (although allowing the valves to be energized on a limited basis under administrative controls for surveillance testing or maintenance activities). This vould ensure that a fire could no longer esuse r,Y;ious closure of valves DH-7A and DH-7B, and therefore relieve the Control Room of needing to send an operator to open breakers BF1148 or BE1157 and, if necessary, open one of these valves by hand. For a Control Room fire, these two manual actions are currently assigned to an equipment operator on the TS minimum shift crew composition and constitute the majority of his safe. shutdown responsibilities.- If these two manual actions were eliminated,-the remaining action that the equipment operator is tasked with performing could be assigned to another on-shift operator. This vill not adversely affect either of the reactor operators' or the other equipment operator's timelines in that these additional actions can be performed after the presently assigned actions are complete and still be accomplished within the necessary timeframe.
Removing power from valves DH-7A and DH-7B during Modes 1, 2, 3, and 4 vould be accomplished by locally opening the valve operators' breakers at their .espective MCCs. This, however, then requires manual action outside the control room during a postulated Lose of Coolant Accident (LOCA) to close the valve operators' breakers at their respective HCCs.
The de-energization of the motor operators for valves DH-7A and DH-7B as-vell as valves DH-9A and DH-9B, vill eliminate the interlock function between them. As stated earlier, the function of the interlock is to prevent valves DH-7A and DH-7B from being open at the same time as valves DH-9A and DH-9B. The control room operators are prevented from shifting pump suctions during a LOCA from the DVST to the Containment Emergency Sump until the BVST low-lov level SFAS Level 5 signal is received. Manual operator action to close the breakers for--
valves DH-7A and DH-7B es well as valves DH-9A and DH-9B in Order te allow the shifting of pump suctions on a BVST low-low level (such as during a LOCA) can be accomplished without undue burden on the shift crew. The basis foc d determination is:
- 1) The need to cAime valves DH-7A and DH-7B (and-also open valves DH-9A and DH-51f during a large break LOCA does not occur until the BVST low-low level SFAS Level 5 signal is received at
Docket Number 50-346 Licensc Number NPF-3 Serial: Number 2084 At t achnien t
'Page 4 approximately 37 minutes post-LOCA (assuming both trains of high and low pressute injection as well ac both trains of containment spray are running) due to the large volume-of the BVST (482,778 gallons minimum per TS 3.1.2.9, Reactivity Control Systems, Borated Vater Sources - Opetating). Cu' rent.
plant cmergency procedures for a large break LOCA specifically require the operators to close the breakers for valves DH-9A and DH-9B. This step in the procedure is reached approximately_
six minutes after the LOCA started (this time was confirmed by the simulator). Closure of the breakers fur valves DH-7A and DH-7B vculd be added to this step in the emergency procedure.-
It takes an operator approximstely three minutes to get all four breakers closed as confirmed by walkdowns conducted by Operations personnel. Once the BVST lov-lov level SFAS Level 5 signal is recalved (at approximately 37 minutes post-LOCA vith both trains of high and lov. pressure injection as well as both trains of containment spray running), the operators vill open valves DH-9A and DH-92. This action, because the interlock vas enabled once the breakers were closed, vill close valves DH-7A and DH-7B, thereby realigning pump suctions from the BUST to the Containment Emergency Sump. The valves, per TS 4.5.2.d.2.b vill take less than 75 seconds to reach their new positions.
- 2) The valve operators and MCC breakers are located in areas that v'll be radiologically accessible post-LOCA. A time-motion evaluation performed by plant radiological control personnel determined that the maximum expected dose accumulated by an operator shutting the four breakers at the HCCs vould be_less than 2.0 Rem. This dose is well vlthin the 10'CFR Part 50, Appendix A, General Design Criteria 19 guideline of 5 Ren and within the 10 CFR Part 20 allovable quarterly' dose of 3 Rem.
This cumulative dose was estimated by conservatively assuming that the operator is exposed to the maximum dose rate for the entire duration required to close the breakers. In reality, the operator is exposed to the maximum dose rate only for a-short portien of'the total duration.
The breakers arc located as follows-(ths breakers for valver.
DH-7B and DH-9B are on the same HCC)?
DH-7A: Auxiliary Building 603' elevation, Room 405 on HCC F lB DH-7B: Auxiliary Building 565' elevation, Room 200 on HCC FllA DH-9A: Auxiliary Building 565' elevation, Room 2.. en HCC F11C.
DH-9B: Auxiliary Building 565' elevation, Room 209 on HCC EllA
- 3) Sufficient personnel are on shift to accomp'11sh the task of closing the breakers for valves DH-7A and DH-7B as well as the-breakers for valves DH-9A and DH-9B. Control room position indication for valves DH-7A and DH-7B is available at Panel C-5716 and can be accomplished by reviring the control power transformer to the HCC source side of the valves' circuit breakers.
l Docket Number 50-346 License Number NPF-3
, Serial Number 2084 Attachment
'Page 5 The proposed revisica to Surveillance Requirement 4.5.2.d.2.b would require that the interlocks be tested only when the valves' motor operators are energized. This vauld ensure their operability during the limited times when the valves' motor operators are energized under
, administrative controls.
l The proposed changes to TS Bases 3/4.5.2 and 3/4.5.3 and 3/4.6.2.1 vould explain the reason for the de-energization of the valves' motor operators during Mode ~ 1, 2, 3, and 4 and are associated administrative changes.
Yhe containment spray system utilizes the BVST or Containment Emergency Sump as its source of spray volume. No changes are proposed for TS i 3/4.6.2.1, Depressurization and Cooling Systems - Containment Spray System (applicable during Modes 1, 2, 3, and 4) because the proposed 'r-changes to TS 3/4.5.2 ad+cuately address the valve operability requirements during Modes 1, 2, 3, and 4. A proposed change to TS Bases 3/4.6.2.1 also cdds an explanation of the recson for the de-energi2ation of the motor operators for valves Dil-9A and Dil-9B during Modes 1, 2, 3, and 4 and is an administrative change.
The existing Surveillance Requirement 4.5.2.d.2.b closure time of less than or equal to 75 seconds for valves Dil-/A and DH-7B to close after the control room operator manually pushes the control switch to open valves DIl-9A and D!l-9B (which should also open in less than or equal to 75 seconds) is not affected by the proposed change. This time is solely a valve response time to the control room operator's manual actica.
Based on the above assessmeat, Toledo Eoison has determined that these proposed changes do not adversely impact safety.
SIGNIFICARf IIAZARDS CONSIDERATION: J The Nuclear Regulatory Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazard exists due to a proposed amendment to an Operating License for a facility. A proposed amendment involves no significant hazards consideration if operation of the facility in accordance with the proposed changes woulds (1) Not involve a significant increase in the probability or consequences of an accident previously evaluated; (2) Not create the possibility of a new or different kind of accident from any accident previously evaluated; ot (3) Not involvt a significant reduction in a margin of safety.
ioledo Edison has reviewed the proposed changes and determined that a significant hazards consideration does not exist because operation of the Davis-Besse Nuclear Power Station, Unit Number 1, in accordance with the proposed changes would la. Not involve a significant increase i- the probability of e$
accident previously evaluated because the temoval of pove to these valves does not affect the large break loss of coolant accident (LOCA) probability.
_ . _ = _. _
Docket Number 50-346 License-Number NPF-3
', Serial Number 2084 Attachment-
~Page 6 lb. Not involve a significant increase in the consequences of-an accident previously evaluated because the changes do not alter the Updated Safety Analysis Report (USAR) LOCA evaluation-and ensure that the pirnt can be safely s.utdown for an 10 CFR Part 50, Appendix R fire. There is sufficient time available under the LOCA sequence of events to close the breakers before the operator is required to transfer pump suctions to the containment emergency i sump. Procedures vill require that the breakers.are closed by the operators. The cumulative radiation dose received by the operator while performing these manual actions vould be below the guidelines of 10 CFR Part 20 and the 10 CFR Part 50, Appendix-A, General Design Criteria 19.
2a. Not create the possibility of a new kind of accident from any accident previously evaluated because adequate time is available under the LOCA sequence of events to the operators to restore power to the Borated Vater Storage Tank (BVST) outlet valves and the containment emergency sump valves when needed. The breakers needed to restore the power to these valves are located in radiologically accessible areas post-LOCA.
2b. Not create the possibility of a different kind of accident from any accident previously evaluated because adequate time is available to the operators to restore power to the BVST outlet valves and the containment emergency sump valves when needed. The breakers needed to restore the power to these valves are located in radiologicallv accessible areas post-LOCA.
t 3. Not involve a significant reduction in a margin of safety because l these are not significant changes to the initial conditions contributing to ace' dent severity or consequences. There is sufficient time available to close the breakers before the operator is required to transfer pump suctions from the BVST to the Containment Emergency Sump.
l l
L CONCLUSION:
l
! On the-basis of the above, Toledo Edison bas determined that the
!' License Amendment Request does not involve a rignificant hazards l- consideration. As this License Amendment Request concerns proposed-changes to the Technical Specifications that must be reviewed by the Nuclear Regulatory Commission, this License Amendment Request does not constitute an unreviewed safety question.
~ ATTACHMENT:
In Attachment 1 are the proposed changes to the Operating License. For informational purposes, also attached to this letter are the TS Bases change proposed for valves DH-9A and DH-9B submitted to the NRC on
- October 4, 1990 as well as a simplified system drawing shoving valves DH-7A, DH-7B, DH-9A, and DH-9B.