ML20247A583
| ML20247A583 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 03/23/1989 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20247A590 | List: |
| References | |
| NUDOCS 8903290150 | |
| Download: ML20247A583 (12) | |
Text
p 10 CFR 50.90 i
1 PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET i
P.CL BOX 8699 l
PHILADELPHIA A. PA.191o1 (21518414000 i
March 23, 1989 Docket No. 50-352 License No. NPF-39 U.S.
Nuclear Regulatory Commission ATTN: Document Control Desk l
Washington, D.
C.
20555 l
SUBJECT:
Limerick Generating Station, Unit 1 l
Technical Specifications Change Request
Dear Sir:
Philadelphia Electric Company hereby submits Technical Specifications Change Request No. 89-03, in accordance with 10 CFR 50.90, requesting an amendment to the Technical Specifications (Appendix A) of Operating License No. NPF-39.
Information supporting this Change Request is contained in Attachment 1 to this letter, and the proposed replacement page is contained in Attachment 2.
i This submittal requests changes to the Technical Specifications to ensure compliance with certain positions pommitted to in the Final Safety Analysis Report (FSAR).
Specifically, FSAR Section 8.1.6.3.6, "BTP-PSB-1 Adequacy of Station Electric Distribution System Voltages" commits the Limerick Generating Station (LGS) to compliance with Branch Technical Position PSB-1,
" Adequacy of Station Electric Distribution System Voltages".
However, the current relay setpoint does not provide full compliance with the FSAR.
This non-compliance was detailed in LGS Unit 1 Licensee Event Report (LER)89-004, submitted to the NRC on February I
10, 1989.
As stated in this LER, the corrective actions to prevent recurrence are the completion of an appropriate modification and the l
I submittal of an associated TS Change Request to the NRC.
This TS j
Change Request is therefore being submitted to. satisfy this commitment.
Although compensatory actions are in effect which provide justification for continued operation during the current Refueling a
Outage, we request that the proposed changes be approved on an exigent basis in order to. allow unit start-up in full compliance with the'FSAR.
We therefore request the proposed TS changes be p(
ffy3290150990333 l
5 p
ADOCK 05000352 i
IDocument Control-Desk Page 2 issued prior to the currently scheduled start-up date of April 19, 1989.
10 CPR 50.91, paragraph (a)(6) provides guidance on the process and requirements for requesting an exigent TS change.
Although the design bases non-compliance was verified to exist in February, 1989, there was substantial uncertainty whether the proposed changes could be implemented prior to start-up from.the current Refueling Outage. -The ability.to procure and install new undervoltage relays, necessary for proper undervoltage protection in.
compliance with the FSAR, was assured only recently.
Accordingly, we-are requesting that this TS Change Request be processed on an exigent basis,'to avoid start-up.with the new-relays set to the.
existing non-conservative TS setpoints, and continuing.to perform the compensatory surveillance initiated when this deviation was identified.
If you have any questions regarding this matter, please contact us.
Very truly yours,
. h.
fo G.
A.
Hunger, Jr.
Director Licensing Section Nuclear Support Division Attachments cc:
W.
T.
Russell, Administrator, Region I, USNRC T.
J. Kenny, USNRC Senior Resident Inspector, LGS-1 T. Gerusky, Director, PA Bureau of Radiological Protection
_ _ _ _ _ - _ - _ _ _ _ _ _ _ _ _ _ ~
I Technical 1 Specification-Changa Request'89.,
1 COMMONWEALTH _.0F PENNSYLVANIA' ss.
COUNTY OP PHILADELPHIA
.J. W.'Gallagher, being first duly sworn, deposes and says:
That he.is Vice President of Philadelphia Electric Company,.the Applicant-herein;'that he has read the foregoing Application fo'r Amendment of Facility Operating Licenses to change the 4160Evolts undervoltage protection relay setpoints, and knows the contents thereof;-
1 and that the statements and matters' set forth therein'are true'and l
correct to the best of his knowledge, information and belief.
0: 1W
.o.
Vice President Subscribed and sworn to before me this 23 day of mnten 1989.
O., hiL (/ OS N~'
N V
,,' Notary Publi'c
.I:
NOTAftAE5EAL JUDITH Y FRANKUN. Ny.ary Public City of Phdadelphia, P*tila, County My Comme.~on reres JJy 28,15531
y.
^\\
ATTACHMENT 1
)
)
l LIMERICK GENERATING STATION
.1 1
s Docket No. 50-352 l
License No. NPF-39 TECHNICAL SPECIFICATIONS CHANGE REQUEST "4160 Volt Bus Undervoltage Relay Setpoint Technical Specifications Change" i
i Supporting Information for Changes - 9 pages i
l I
i l
l
_z___._____._____________._._______.____.
a
e Docket No. 50-352 I
Philadelphia Electric Company, Licensee under Facility
)
Operating License NPF-39 for Limerick Generating Station (LGS)
Unit 1, hereby requests that the Technical Specifications I
l contai.ed in Appendix A of the Operating License be amended to I
1 revise certain 4160V bus undervoltage protection relay setpoints i
as proposed herein.
The proposed changes are indicated by J
vertical bats in the margin of the page 3/4 3-38, and provided in I
I Attachment 2.
{
a I
Pni1adelphia Electric Company requests these changes to provide full compliance with the Limerick Generating Station (LGS) des 2gn bases.
We request these changes be effective prior to startup trom the second Refueling Outage.
This Change Request provides a discussion of the 4160V l
bus protection scheme, a description of the proposed TS changes, information supporting a finding of a No Significant Hazards l
Consideration, and information supporting an Environmental l
Assessment.
System Discussion Tbs safety related function of the degraded' grid-
.mervo] rage relays discussed herein is to provide a second level l
l of undervaltage protection to the Class 1E equipment in accordance with the guidance of Branch Technical Position (BTP).
_2_
i Docket No. 50-352 l
i PSB-1, " Adequacy of Station Electric Distribution System".
BTP-PSB-1 recognized the inadequacy of existing undervoltage protection schemes which typically provided only a single level 1
(i.e.,
a loss at power relay) of undervoltage protection.
BTP-j PSB-1 states in part that a second level of undervoltage protection with a time delay is needed to protect the Class lE equipment under degraded power supply conditions which would not actuate s loss of power relay typically set at 70% of nominal, j
Concurrent with this protective function, BTP-PSB-1 states that the settings on these relays be such that the likelihood for 4
spurious separation of Class 1E systems from the orfsite power system be minimized.
The current relay setpoint (90% of 4160V) was selected in accorcance with the guidance in BTP-PSB-1.
To ensure adequate voltage levelc at the terminals of the 480V Class 1E loads, we determined that a minimum of 92% of 4160V was required on the 4160V tuses, with a tap changer setting of 5% boost on the 4160-480V load center transformers.
The most accurate undervoltage l
relay available, when installing the protective equipment, was a Brown Boveri model ITE-27D.
This relay provides a +2% setpoint tolerance with a 3% pickup-to-dropout ratio.
This ratio is a relay characteristic which specifies the difference between the trip setpulc.t and the value required for the relay to reset.
Therefore, it a 92% setting was used, this would translate to a maximum relay actuation at 94% and a maximum reset at 97%.
These _ _ _ _ _ _ _
y--_______--
Docket No. 50-352 actuation and reset voltage levels were considered too high, since they may have created the possibility for spurious trips, l
which would be contrary to the guidance of BTP-PSB-1; Considering these facts, a 90% relay setting was chosen for these relays.
Subsequently, the St boost tap setting was determined to result in.480V equipment damage because of elevated voltages (above equipment rating) under certain loading conditions.
To i
correct tnis situation, the tap setting of the M,60-480 volt transformer was changed to 0% without revising the setting of the ITE-27D relay.
Maintaining the relay setting at 90% under this condition could result in undetected. degraded voltages at the 480V level (below the minimum required to ensure proper operation l
of 480V Class lE loads).
Subsequent to tne discovery of.the inadequate relay i
setpoints, calculations were performed to determine the optimal setpoint t.) satisfy BTP-PSB-1 guidance.
Based on the I
calculaticna, the proposed TS setpoint is 94% of 4160V, with a top setting of 2.5% boost.
Use of the existing ITE-27D relays would result in an unacceptably high reset voltage (considering a maximum +2t tolerance and 3% pickup-tp-dropout ratio, reset would ocent at about 99%).
For this reason, these relays are being replaced t.sith Brown Boveri model ITE-27N relays.with a tolerance of +0.3%. tad a pickup-to-dropout ratio that can be set at t b
m u
Docket No. 50-352 approximately 0.51.
Tne tight setpoint tolerance and pickup-to-dropout ratio of the new relay provides the performance necessary to help prevent spurious tripping of the supplying offsite source and also allows relay reset at a maximum value of about 0.8%
dboVe tne TS t'. 0 1 p G e t p o i n t.
'ihis TS cnange request will ensure compliance with the design bac2s specified in FSAR Section 8.3.6.3.6 with regard to satisfying the minimum required voltage levels and equipment protection in accordance with BTP-PSB-1.
Description of Changes As discussed above, the current undervoltage (UV) relay setpoints are 90% of 4160 volts.
Replacement of the existing relays will permit a relay setting which provides UV relay trip at 941 et 4160 volts, after the associated time delay.
This setting ca the new relay will provide compliance to the design bases comm.itted to in FSAR Section 8.1.6.3.6.
ti.e., PSB-BTP-1).
Therefore, tne setpoints shown on page 3/4 3-38 for relays 127Z-11X0X will be revised to 3910 +11 volts and 111.7 volts 10.3, and the allowable value changed to 3910 119 volts, and 111.7 volts 10.5.
These latter values reflect the 120 volt side of the sensing device (i.e.,
the UV relay).
~5-l 1
1
-v a
e l
+
.=
Docket No. 50-352
)
.I l
Safety'Acsessment Tne NRC.prov.ided guidance in BTP-PSB-1 with respect to 1
' l criteria fcr maintaining' adequate bus voltage to Class IE 3
equipment to prevent equipment damage.
The. protection scheme l.i providea by PCCo for-LGS was accepted as adequate as detailed in
-the NRC Satety Evaluation Report (SER), NUREG-0991,. issued in' 4
August 1963 for LGS. Units 1 and 2.
The' existing setpoint of.90%.
was chosen-to Satisfy the guidance of PSB-BTP-1 while considering
.l the limit.ations of. the equipment available.
l P.eplacement'of the existing relays will facilitate relay i
I settings for' dropout'at.94%.of 4160V, without the jeopardy of causing upurious. tripping,.which would exist if the current J
relays were set to assure tripping at 94%.
The proposed TS change is necessary to implement the ralay setpoint changes.
The-E proposed 94t TS setpoint will ensure minimum bus voltages to.
Class lE equipment are maintained ~while also preventing spurious; bus tripping., This will result in full compliance ~with the design boccu.
Information Supporting a Finding of No Significant Hazards Consideration We have concluded that the proposed changes to the LGS TS,'whicn change the undervoltage relay setpoints, do not constitute a significant. hazard consideration.
In support'of w
- ^
L_-i___-_:_--_
Docket No. 50-352 this determination, an evaluation of each of the three standards
]
1 set forth in 10 CFR 50.92 is provided below.
j 1
i i
A.
The proposed changes do not involve a significant t
increase in the probability or consequences of an accident previously evaluated.
Pr.c proposed relay setpoints will ensure that adequate j
voltages are available to all Class lE equipment in all I
modes of plant operation.
The. proposed changes will provide consistency to the design objectives approved by the NRC and committed to in the design bases.
The l
current setpoints do not fully comply with those objectives.
Therefore, the proposed changes will not result in a significant increase in the probability or.
consequences of an accident previously evaluated.
i D.
The proposed changes do not create the possibility of a new or different kind of accident from any-accident-previously evaluated.
The proposed changes do act involve'any design changes to the undervoltage protection scheme.
Since the proposed TS changes will result in system operation consistent with the design bases (which will remain the same), the current FSAR will remain complete and _____- __-___- ____-_ - ____________- _ - _ _ _ _ _ _ _ _ _
y.
Docket No. 50-352 accurate in its discussion of the licensing basis events anc in analyzing plant response and consequences.
Therefore, no equipment is adversely affected, nor could the proposed changes involve any potential initiating e<ents which vould create any new or different kind of i
nacident.
As such, the plant initial conditions l
l utilized for the design basis accident analyses are j
1 l
still valid.
Thus, the proposed changes do not create the possibility of a new or different kind of accident trom any accident previously evaluated.
I l
C.
The proposed changes do not involve a significant reduction in a margin of safety.
l 1
i 1
As discussed above, the proposed changes do not change the design bases but will result in full compliance with i
the PSAR commitment.
As such, an incremental 2mprovement in the margin of safety _uill result.
l Tneretore, the proposed changes do not involve a-
)
i significant reduction in a margin of safety.
)
i Information Supporting an Environmental Assessment I
i An environmental assessment is not required for the changes proposed by this Change Request because the requested changes conform to the criteria for " actions eligible for __ -
. <. ~
. Docket No.L50-352 categori'eal exclusion"'as-specified in 10CFR51.22(c)(9).' The:
requesteo changes'will.haveino' impact onithe environment.
This Change-Request does not involveta;significant hazards
'co'nsideration as. discussed in thesprecedingtsection.
This Change Request-does not. involve aisignificant change in,the types ors significant increase in the amounts of any effluents that may be released.offsito.
In addition, this Change. Request doesinot l-
-involve a significant increase inLindividual or cumulative 1
l-occupational. radiation exposure.
Conclusica Tne Plant Operations' Review Committee'and the Nuclear Review' Board have reviewed these proposed changes to the TS and
'have concluded that they do not involve a.unreviewed safety questions or a significant hazards' consider.ation, and will not endanger the health and safety of the public. u
. _ _ _ _ _ _ - _ _ - -