ML20117J842
| ML20117J842 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 04/19/1985 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| CON-#285-662 NUDOCS 8505150235 | |
| Download: ML20117J842 (8) | |
Text
7' g
e PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.Ol BOX 8699 PHILADELPHIA. PA.19101
)
SHIELDS L DALTROFF ELECTRIC PRODUCTION Docket Nos.60-352 50-353
!!r. Richard U. Starostecki, Director Division of Reactor Projects
-United States Nuclear Regulatory Commission Region 1 631 Park Avenue Eing of Prussia, PA 19406 i
SUBJECT:
Limerick Generating Station, Units 1 and &
Technical Review of the AC and DC Electric Power Systems by Brookhaven National Laboratory (BNL)
REFERENCE:
- Letter, R. h. Starostocki to S.
L.
Daltroff dated !: arch 21, 1985
Dear ?:
- r. Starostocki:
This letter provides Philadelphia Electric Company's response to the subject letter.
Le believe that ENL's selection of these systems for their technical review is a credible use of the Probabilistic Risk Assessment (PRA).
Response to Open Items listed in Section 12.1 of the BNL Report In accordance with our discussion with R.
l'.
Gallo of your staff April 15, 1985, our staff will be prepared to discuss the following open items listed in Section 12.1 of the BNL Technical Report during the BNL inspection scheduled for the the week of April 22, 1985.
1.
Loose metal components in 4LV Gwitchgcar.
2.
Broken floor grating in Diosc1 Generator (D/G) roops.
3.
D/G ventilation panel labels.
4.
Dobris in D/G rooms.
6.
Alarm response cards for local safety related pancia.
l 8505150235 850419
~
PDR ADOCK 05000352-5O/
G PDR
]
~
r
^"
4 lir.) Richard ti. -Starostecki April 19, 19ub-Page 2 11.-
D/G vent-fan discharge damper position / Indication.
13.
Refueling' cycle D/G maintenanc'e procedures.
147 f Vendor recommended D/G operational checks.
15.; lD/G physical' condition discrepancies.
i l
16.
Verification of D/G cooling system within design limits.
l.
j 17..
Trending of D/G operating parameters not performed.
t l
' Loss'of offsite power procedure items.
19..
j i
20.-
Station blackout procedure items.
l
. Our comments and actions addressing the remainder of the open
- items listedfin Section 12.1 of the BNL Technical Review report-
.'are as follows:
[
S.,
Battery. Charger 1 Load Testing Less Than Required.
Response
l t.
.The apparent discrepancy exists because the wording used to describe the11oadJin1 Preop Test 2.l'is incomplete.
It should state its purpose as a verification that the charger.
can recharge the battery from a fully discharged condition l
while supplying normal, shutdown, or-post accident loads.
.The fact that the test did prove this capability is evident based on a comparison of the load values used<in the-preop
- test
- against'FSAR Tables 8.3-18 through 8.3-26, which list-the emergency loads.
This comparison shows that the-loads-c.v; used encompassed the normal, shutdown or post accident
_ loads.
7.
Sufficient: completion of 33EV 'Of f site Power Source.
Response
.Section 8.2.1.1 of the Limerick FSAR describes the 33EV "line as a potential ~ third offsite source for emergency use in the event that either of the normal offsite sources is lost. ' The degree of ccmpletion of this potential offsite source. ~is further explained in FSAR Section 8.2.1.1 as follows:
F.
X-a.
.Mr.
Richard H.
Starostecki April lv, 1985 Page 3 a)
A spare 14PVA 13.2/33-4.16EV transformer is located onsite.
b)
Underground conduit is installed to connect each safeguard transformer location with the 33EV s.;
circuit breaker terminal yard.
t The work required to complete the installation is recognized in FSAR Section 8.2.1.1 as follows:
a)
The faulty safeguard transformer will be removed and physically replaced by the spare.
b) 33EV cable will be pulled into the underground conduit.
c)
A 33EV aerial tap will be made.
d)
Reconnection of control and protective relaying is required.
Paragraph 8.2.1.1 does not state that the control and
- protective relay wiring would be previously installed.
It states that in the event of a failure of either Unit 1 or Unit 2 safeguard transformer requiring a repair time greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the faulty transformer will be removed and physically replaced by the spare.
The reference to a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> restoration time in FSAR Section 8.2.1.1 is intended as Philadelphia Electric Company's estimate of a reasonable time period for accomplishing the
-required actions to connect the third offsite power source to avoid the shutdown that is required by the Technical Specifications upon loss of one offsite power source.
Technical Specification 3.8.1.1 establishes that two offsite sources are a limiting condition for operation for operational conditions 1, 2, and 3.
Action 3.8.1.1.f requires the plant to be removed from service to at least hot shutdown within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the initial 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed for the restoration of two offsite power sources.
The provision for the third offsite power source is only to maximize plant availability should equipment failure cause a long-term loss of one of the existing offsite sources.
t Therefore, no credit has been taken in any accident 4 T' analysis for the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> restoration.
e 4,
e
~t
.l s
s
. !:r,. Richard b.
Starostecki April 19, 19u5 Page 4 i
8.
Physical Independence of 33EV and 220LV Sources.
Response
As shown in FSAR Figure 8.2-3, the 33LV feed to the plant transformer does not go through the 220KV switchyard.
A radial feed from the 33KV line provides auxiliary power to the 220EV switchyard.
This radial feed is one of 3 sources of auxiliary power, and all auxiliary load in the switchyard can be powered from either of the other two cources.
The radial feed is aerial to a point immediately 3
inside the switchyard fence where it makes a transition to
)
underground duct. fIf it becomes necessary to use this potential offsite source, the present feed to the
- switchyard auxiliary equipment will be disconnected, an aerial tap made, and cables to the 33RV oil circuit breaker 3
and the replacement transformer will be pulled through s
existing duct.
With the exception of the auxiliary power s
,y is [
feed, which will be disconnected if it is Qsed as an k
offsite source, there is no other 220EV substation equipment in close proximity to the 33LV circuit.
)
Uc believe that the potential 33KV offsite source meets the physicc1 separation requirements of General Design Criteria 17 of 10 CFR 50 Appendix A.
9.
Switchyard Disconnect Position.
Eesponte Limerick electrical drawing E-1, Rev. 12 shows disconnect switches Nos. 4B7 and 4BS open with an associated note,
" Blocked Open".
Procedure S35.8.0 Rev. O calls for disconnect switch No. 4B7 to be closed.
Our review of this p
discrepancy has concluded that it is acceptable for either one or both of these switches to be open to block power flow via the 4B autotransformer.
Therefore, it is of no operational-consequence that disconnect switch No. 4B7 was closed rather-than open.
Accordingly, Philcdelphia Electric Company has taken action to remove the note
- " Blocked Open" from drawing El.
10.
D/G Vent Fan Capability and D/G Operability.
Ecsponse In accordance with our commitment to the BNL technical specialist during his tour, an enginncring evaluation, which shows that for outside tempc. 3ures up to 75 degrees Fahrenheit one fan will suffice, as been formally transmitted to Limerick Cener-
- ation.
a 3
,I'
'5
~st
f?
_g
~
fir. Richard U.
Starostecki-April 19, 1985 Page 5 12.
'D/G' Exhaust into Reactor Building Ventilation Intake.
L
Response
l'
[l The-phenomena of diesel generator exhaust gases entering l
the reactor enclosure intakes was first observed during preoperational testing.
Ehile this problem is not a
(
nuclear safety concern (since the reactor enclosure intakes will; isolate upon a LOCA signal), a concern has-been expressed by Philadelphia Electric Company regarding the potential personnel hazards of inhaling the exhaust fumes and the spurious fire alarms which result from the presence-of smoke inside the reactor enclosure.
I A program was developed by Philadelphia Electric Company to l
determine a cost-effective solution to this problem.
The program consisted of wind tunnel model testing to determine l
the optimum stack configuration, analysis of the results to cdetermine the critical windspeeds and directions, and implementation of modifications to the exhaust stacks.
L-
-The results of the wind tunnel testing have shown that an
-unimpeded vertical discharge of the effluent will produce a substantial decrease in exhaust concentrations at the reactor enclosure intakes.
Modification Design Change
[
' Package (MDCP) No. 416, Revision 1, has therefore been
[-
issued,to remove the existing 90-degree elbows.on the
[
exhaust stacks above the' diesel generator roof leaving a 7-
'1/2' foot'verticalistack.
The MDCP also includes appropriate automatic drainage provisions on the exhaust silencers to ensure the. continuous removal of water which may accumulate at the. base of the stacks.
This MDCP is currently being implemented in the field, with completion on-all.four diesel generator units expected by April 30, 1985.
Further extension of the stack height will be considered based on additional analysis of test results and operating experience.
18.
. Positioning of ESU Throttle Valve for D/G Cooling.
The Emergency Service Uater (ESU) return from each diesel generator' skid passes through a manual globe valve (11-1005A, D, C,
D, as applicable).
The inspection report-presented three finding related to these valves.
r-t e, -
Z:r. Richard E. Starostecki April 19, 1965 Page 6 a)
The Limerick Probabilistic Risk Assessment (PRA)
AC Power fault trees lists the valves as normally open-fail closed.
Response
Figure 8, Shoot 4 of 11 of the Limerick PRA System Level Fault Trees correctly shows a normal open-fail closed designation for these valve's.
This is an analytical convention intended to assign a numerical probability (for PRA analysis) associated with the possibility of flow interruption due to mispositioning of this valve, or failure of the valve stem in the closed position.
Analogous conventions are used throughout all System Level Fault Trees for representing the probability of failure associated with manual valves.
b)
Procedure Sll.l.A Check Off List-1 (COL-1) states that the valves for the 4 D/G's are throttled open (2-1/8, 2,
2-1/10, and 2 turns respectively).
Response
The Emergency Service Kater System requires flow balancing (throttling of certain manual valves) to ensure that adequate cooling water flow is provided to all heat exchangers in the system.
Procedure Sll.l.A (COL-1) indicates the currently approved positions of these valves based upon system flow analyses and flow balancing test results.
c)
Procedure S92.1.N (COL-1) states that these valves are open (i.e., full open).
Response
Procedures S92.1.N (COL-1, 2,
3, 4), which are the individual diesel generator checkoff lists, will be revised to reflect the appropriate positions of these valves as listed in Sil.l.A (COL-1).
s, lit. Richara I;. Starostocki April 19, 19o3 Page 7 If you should have any ques tions, please do not hesitate to contact us.
Very truly yours, e a/
v
/
cc:
J.
T. Liggins, Site Inspector A. Schwencer, Division of Licensing, USNRC (See Attached Service List)
M
- c. ;
j
-g A.%
e
.s cc:- Judge Helen F.'Hoyt
' Judge Jerry Harbour
. Judge Richard-F.' Cole
' Troy B. Conner, Jr., Esq.
Ann P. Hodgdon, Esq.
-!!r.-Frank R. Romano
.11r. Robert L.. Anthony-fic.. Phyllic Zitzer -
Charlec U.
Elliott, : Ecq.
. Zori G. Ferkin, Ecq.-
fir. Thoman lGerusky Director,: Penna. Emergency !!anagement Agency
~
! Angus Love, Ecq.
David Uersan, Esq.
Robert J. Sugarman, Esq.
Martha U. Bush, Esq.
Spence U.
Perry, Ecq.
Jay 71. Gutierrez,. Esq.-
Atomic Safety-& Licencing Appeal Board
. Atomic Safety & Licencing Board Panel Docket'& Service'Section.(3 Copies)
-James.Wiggins Timothy'R. S. Campbell 1/16/05 l'
r L