ML20073L100
| ML20073L100 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 04/11/1983 |
| From: | Vassallo D Office of Nuclear Reactor Regulation |
| To: | Vermont Yankee |
| Shared Package | |
| ML20073L104 | List: |
| References | |
| DPR-28-A-078 NUDOCS 8304200547 | |
| Download: ML20073L100 (12) | |
Text
_
99 %q
.,*i
'g UNITED STATES NUCLEAR REGULATORY COMMISSION y
- g L
r wAssiwcioN. o. c. rosss o%,,
S
,o
- ...+
VERtONT YANKEE NUCLEAR POWER CORPORATION DOCKET NO. 50-271 VERMONT YANKEE NUCLEAR POWER STATION
^ -
AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 78 License No. DPR-28 1.
The Nuclear Regulatory Comission (the Comission) has found that:
A.
The application for amendment by Vermont Yankee Nuclear Power Corporation (the licensee) dated February 22, 1983 complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act),
and the Commission's rules and regulations sit forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Comission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public and (ii) that such activities will be conducted in compliance with the Comission's regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and l
l E.
The issuance of this amendment is in accordance wi.th.10 'CFR Part 51 of the Comission's regulations and all applicable requirements
~~
have been satisfied.
2.
Accordingly, the license is amended by changes to the Technical Specifi-l cations as indicated in the attachment to this license amendment, and paragraph 3.B of Facility Operating License No. DPR-28 is hereby amended to read as follows:
B. Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 78 are hereby incorporated in the license.
The licensee shall operate the facility in accordance with the Technical Specifications.
8304200547 830411 PDR ADOCK 05000271 P
PDR t
2-3.
This license amendment is effective as of the date of issuance.
.FOR THE NUCLEAR, REGULATORY C0911SSION
. ur - c; - w ca,
m
., g,3
..) : ^ :-
lr,5., v ekshlg N' : '
' X.l' > '
s.
.- 7 e -
+
3,
~
Domesic B. Vassallo, Chief Operating Reactors Branch #2 Division of Licensing
].
Attachment:
Changes to the Technical.
Specifications
~ *~
Date of Issuance April 11, 1983 I
e
ATTACHMENT TO LICENSE AMENDMENT NO. 78 FACILITY OPERATING LICENSE NO. DPR-28 DOCKET NO. 50-271
.,..,m.
.c
--' 9g.
2
+.
~ :/ '
~ ~.
~
,, s....::
...., ;. u.
..a..
..,...n...
Revise the Technical Specifications by removing the following pages and inserting identically numbered pages.
The revised area is identified by a vertical line.
4 6
'5 b 14a 19 21 21a 29 30 e
e
?
VYNPS 1.1 SAFETY LIMIT 2.1 LIMITING SAFETY SYSTEM SETTING --
For the purpose of performing special stability testing when the mode switch is in the RUN position,l the APRM flux scram
' trip setting, shall' be:
~
~l $.Q S< 0.66W:ff;r %%
85
.;t. z For no combination of loop recirculation flow rate and core thermal power shall f
I the APRM flux acram trip setting be
,'allowedtoexceedjl2p1ofratedthermal
" power.
Her' During operation under the provisions of i
2.1.A.I.b, the special HAPLHCR limits of 3.11.A shall apply and such operation i
shall be~ limitedito the duration of pump trip 'and stability ' test s.
Adjustments
~ for thehratio;ofiMFLPD to FRP greater than 1.0 'are notirequired while conditcting special testing under this provision.
c.
Flux Scram Trip Setting (Refuel or
. Startup and Hot Standby Mode)
When'the reactor', mode switch is in the REFUEL or STARTUP.' position, average power range sonitor/(APRM)f scram shall be set
" down to _ less than' orfequal to 15% of rated neutroniflux Jexcept as allowed by Note 13 of Tablel3.1.1). The IRM flux scram setting shall be set at less than or equal to 120/125 of full scale.
'. {. ;
l GN. 9-
\\
p h:-.
Sb
= I ((f l
Amendment No, pf, 78 1
yn t?
Dt
~
+ <
- y. v e
?
n '
-y' 1
VYNPS d~
- (~
n APRM Flux Scram Trip Setting (Run Mode) i)
\\
$ T? t t
r The scram trip setting must be adjusted to ensure that the LilCR transient peak is not increased for any combination of i
HFLPD and reactor core thermal power.
If the scram requires a change due to an abnormal peaking condition, it will be accomplished by increasing the APRM gain by the ratio in Specification 2.1.A.I.a. thus assuring a reactor scram at
..F lower than design overpower conditions.
in.,
~.
4 ;4;;o ag isrequiredtoassurejfuelcladdinh.% integrity when Analyses of the limiting transients show that no scram adjustment the transient is initiated from~the operating limit HCPR (Specification 3.11C).
f 7:
pW l
Flux Scram Trip Setting (Refuel or Startup and llot Standby Mode) l For operation in the startup mode while the reactor is at low pressure, the reduced APRMfscram settingito 15% i rated power provides adequate thermal margin betueen the setpoint and the safety 11mit,u25%cof;therated'%(Duringanoutage when it is necessary to check refuel interlocks, the mode switch must be moved to}the'startup position;/ Since the APRM reduced scram may be inoperable at that time due to the disconnection of the LPRMs,'it is required that the IRM scram and the SRM scram in noncoincidence be in effect. This will ensure that adequate thermal margin is maintained
~
between the setpoint and the safety limit.) The margin is adequate to accommodate anticipated maneuvers associated with station startup. Effects of increasing pressure at zero or low void content are minor, cold water from sources available during startup is not much colder than that aircady in the system, temperature coefficients are small, and control rod patterns are constrained to be uniform by operating procedures backed up by the rod worth' minimizer.
Worth of individual rods is very low in a uniform rod pattern. Thus, of all possible sources of reactivity input, i
uniform control rod withdrawal is the most probable cause of significant power rise. Because the flux distribution associated with uniform rod withdrawals does not involve high local peaks, and because several rods must be moved to change power by a significant percentage of rated power, the rate of power rise is very. slow. Generally, the heat flux is in near equilibrium with the fission rate.
In an assumed uniform rod withdrawalf approach' toithe_ scram level, the rate of power rise is no more than 5% of rated power per minute, and the APRM system would be more(than adequate to assure a scram before the power could exceed the safety limit. The. reduced APRM scram remains active until the mode switch is placed in the RUN position. This switch can occur when reactor pressure is greater than 850 psig.
i The IRM system consists of 6 chambers, 3 in each of the reactor protection system logic channels.
he IRM is a 5-decade instrument,which covers the range of power level between that covered by the'SRM and the'APRM.9 The 5 decades t
i i
are covered by the IRM by means of a range switch and the 5 decades are broken down into 10 ranges each being one-half of a decade in size.
The IRM scram trip setting of 120/125 of full scale is active in eachirange of the IRM.
For example, if the instrument were on range 1, the scram setting would be a'120/125' of full scale for that range; likewise, if the instrument were on range 5, the scram would be 120/125 oflfulliscale on;that? range. Thus, as the IRM is ranged up to accommodate the increase in power level, the scram trip setting.is falso' rang'ed;up. The most significant sources of reactivity change during the power increase are due to control: rod ~ withdrawal ( For in sequence cont rol rod withdrawal, the rate of change of power is slow enough due to the physicalilimita'tionL ofl withdrawing
~
cor/.a1 rods, that heat flux is in equilibrium with the neutron flux and an IRH scram would result 1n a reactor shutdown well before any safety limit is exceeded.
' O.;
- x Amendment No. pf, 78 nw ili-l ;
l l
SjV
+
UYNPS TABLE 3.1.1 REACTOR PROTECTION SYSTEM (SCRAM) INSTRUMENT REQUIREMENTS j
f' o
Modes in Which 9c Functions Must be Minimum Number?
- Required conditions When l
Operating Operating Instrument
- : Minimum Conditions For Refuel Startup Run Channels Per
[ Operation Are Not Trip Function Trip Settings (1)
(13)
Trip System (2)
' Satisfied (3)
[
.s,.
t ;., j A
- 1. Mode Switch X
X X
1/
in Shutdown j,' -
3 :.,c.
- 2. Manual Scram X
X X
1 d' $
A a
e'
- 3. IRM A
liigh Flux
~< 120/125 X
X X(11) 2 l
INOP X
X X(11) 2 A
-5,k
- 4. APRM Iligh Flux
< 0.66WF54%(4)
X 2'
j %..x.,
9
.:y A or B s
(flow bias)
.p.
J' j (reduced) i M>:
M" A
liigh Flux
< 15%
X X
2-X 2(5)
G A or B j
INOP i
Downscale
> 2/125 X
2
'E A or B
_ 1055 pstg X
X X
2
?
A
- 5. Iligh Reactor Pressure en b [(,,
A
- 6. Iligh Drywell
< 2.5 psig X
X X
2'
{.z ; ' '
Pressure N;
- 7. Reactor 1.ow (6) > 127.0 inches X
X X
2
?
A Water I.evel
'y;.
l Volume liigh
- 24 gallons X
X X
2
- U A
- 8. Scram Discharge <
.y t-Level
- } S?/ ]'
I S
19 l
.y.,
l AmendmentNo./),fd,78
.Ih y.
t p
j l
4 VYNPS NN 4 0, vr-a-
P:
TAELE 3.1.1 NOTES 0
1.
When the reactor is suberitical and the reactor water temperature is less than 212 F, caly the following trip functions need to be operable:
i; p.s e, i
a) mode switch in shutdown
-p '
b) manual scram l
c) high flux IRM or high flux SRM in coincidence l
d) scram discharge volume high water level n ->
4 2.
Whenever an instrument system is found to be inoperable, the instrument system. output relay shall te tripped immediately. Except for HSIV & Turbine Stop Valve Position, this action shall result in trippi,ng,the trip system.
.a, 1
3.
When the requirements in the column " Minimum Number of Operating Instrument Channels Per Trip System" cannot be met for one system, that system shall be tripped.
If the requirements cannot be met for both trip, systems, the appropriate actions listed below shall be taken:
V, a)
Initiate insertion of operable rods and complete insertion of all operable rods within four hours.
b)
Reduce power level to IRM range and place mode switch in the "Startup/ Hot Standby" position within eight hours.
c)
Reduce turbine lead and close main steam line isolation valves within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
d)
Reduce reactor power to less than 30% of rated within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
6 lbs/hr core 4
"W" is percent rated drive flow where 100% rated drive flow is that flow equivalent to 48 x 10 flow.
5.
To be considered operable an APRM must have at least 2 LPRM inputs per level and.at least a total of 13 LPRM inputs, except that channels A, C, D, and F may lose all LPRM inputs from the companion APRM Cabinet plus one additional LPRM input and still be considered operable.
6.
The top of the enriched f uel has been designated as 0 inches and provides common reference level for all vessel water level instrumentation.
I 7.
Channel shared by the Reactor Protection and Primary Containment Isolation Systems.
'b
?-
1 A,y 6.
An alarm setting of 1.5 times normal background at rated power shall be _ established to' alert the ; operator to abnormal radiation Icvels in primary coolant.
t 21 P.;
],+
9 AmendmentNo.[,78
3-7
,v-3-
a.
%,' d
^/
VYNPS 9.
Channel signals for the turbine control valve fast closure trip shall be derived from the same. event or events which cause the control valve fast closure.
- {'s, 10.
A' turbine stop valve closure and generator load rejection bypass is permitted when the; firstle' age turbine t
d' F.
pressure is less than 30% of normal (220 pata),
d,
.u.;
11.
The IRM scram is bypassed when the APRMs are on scale and the mode switch is in the run position.
g 12.
For spec-ial stability tests, the APRM flux: scram shall be < 0.66W + 85% for the duration of;. testing.
Adjustments f or the ratio of MFLPD to FRP greater.than 1.0 are not required while conductirig'special tests.
ly
+
13.
WhileperformingrefuelinterlockcheckswhichrquirethemodeswitchtobeinStartup,[thejreducedAPRMhigh flux. scram need not be operable provided:
.g,
' l ' W, I 7.'
hk.
E-a.
The following trip functions are operable:
W A
1.
Mode switch in shutdown, m
2.
d'
'?
3.
liigh flux SRM scram in noncoincidence, j
P 5.
Scram dLscharge volume high water level, and; b.
No more than two (2) control rods are withdrawn. The two (2) control rods that can be withdrawn cannot be f aced adjacent or diagonally adjacent.
.b. p,
d.
T.. ;
9 T
k I
k
.. a 4
t j_
a
+
','t j
e I
f.
w AmendmentNo.[,78 4
x 711 3
'c h
7 VYNPS 3.1 (cont'd)
Iligh radiation levels in the main steam line tunnel above that due to the normal nitrogen.and oxygen radioactivity is an indication of leaking fuel. A scram is initiated whenever such radiation level exceeds three times normal background.
The purpose of this scram is to reduce the source of such; radiation to the extent necessary to prevent release of radioactive materials to the turbine. An alarm is initiated whenever the rad i a t ion level exceeds 1.5 times normal backg* ound to alert the operator to possible serious radioactivity spikes due to abnormal core behavior. The air ejector off gas monitors serve to back up the main steam line monitors to provide further assurance against release of radioactive materials to site environs by isolating the main condeuser off gas line to the main stack.
The main steam line isolation valve closure scram is set to scram when the isolation valves are 10 percent closed from full open in 3-out-of-4 lines. This scram anticipates the pressure and flux transient, which would occur when the valves close.
By scraming at this setting, the resultant transient is insignificant.
A reactor mode switch is provided which actuates or bypasses the various scram functionsjappropriate to the particular plant operating status.
The manual scram function is active in all modes, thus providing for manual means of rapidly inserting control rods during all modes of reactor operation.
The IRH system provides protection against short reactor periods and, in conjunction with the reduced APRM system provides protection against excessive power levels in the startup and intermediate power ranges. A range monitor (SRM) system is also provided.to supply additional neutron level information during startup sou rc e and can provide scram function with selected shorting links removed during refueling. Thus, the IRM and the reduced APRM are normally required in the startup mode and may be required in the refuel mode. During some refueling activitics which require the mode switch in startup; it is allowable to disconnect the LPRMs to protect them from damage during under vessel work.
In lieu of the protection provided by$the reduced APRM scram, both the IRM scram and the SRM scram in noncoincidence are used to provide neutron monitoring protection against excessive power Icvels.
In the power range, the normal APRM system provides required protection. Thus, the IRM pystem and 15% APRM scram are not required in the run mode.
The requirement that=the IRMs be inserted in the core until the APRMs read at Icast 2/125 of f'ull scale assures that there is proper overlap in the neutron monitoring systems.
i If an unsafe failure is detected during surveillance testing, it is desirable to determine as soon as possible if other f ailures of a similar type have occurred and whether the particular function involved is still operable or capable of meeting the single failure criteria.. To meet the requirements of Table 3.1.1, it is necessary that all instrument channels in one trip system be operable to permit testing in the other trip system.
- Thus, YJ 29 Amendment No. y[, 78 I
VYNPS 3.1 (Continued) when failures are detected in the first trip system tested, they would have to be repaired before testing of the other system could begin.
In the majority of cases, repairs or replacement can be accomplished quickly.
If repair or replacement cannot be completed in a reasonabic time, operation could continue with one tripped system until the surveillance testing deadline.
$u The requirement to have all scram functions, except those listedinTable3.1.1,operableinjthel" Refuel" mode is to assure that shifting to this mode during reactor operation does not diminishrthe need for[the reactor 1
protection system.
- 4 ;
s The ability to bypass one instrument channel when necessary to complete surveillance testing.will preclude contin'ued operation with scram functions which may be either unable to meet the single failure criteria or completely inoperable.
It also eliminates the need for an unnecessary shutdown 71f.;the remaining, channels and subsystems are found to be operable. The conditions under which the bypass. ls ' permitted: reqdire;an immediate determination that the particular function is operable, llowever, during the time (a bypass ihjapplied, the function will not meet the single failure criteria; therefore, it 'is prudent to limit thel time the bypass is in
~
effect by requiring that surveillance testing proceed on a continuous basis and that the bypass ~be removed as soon as testing is completed.
.jl 5
Sluggish 1,dicator response during the perturbation test will be indicative of a plugged instrument line or closed instrument valves. Testing immediately after functional testing will assure'the operability of the theoperabilityofthereactorpressuresensors.as'wel1[as{thereactor instrument lines. This test assures level sensors since both parameters are monitored through the same instrument lines.
",. c #g v~
The independence of the safetysystemcircuitryisde,terminedbyoperationofthescram'testfswitch. Operation of this switch during the refueling outage and following maintenance on these circuits will. assure their continued independence.
The calibration frequency, using the TIP system, specified for the LPRMs will provide assurance that the LFRM input to the APRM system will be corrected on a timely basis for LPRM detector depletion characteristics.
- .y ny
' ff; ~ \\
- 1 30 l
s s9;i
?
.. ~.
s Amendment No. 78 p
- [
'c, UNITED STATES
{ j{ /
i
.,, y h NUCLEAR REGULATORY COMMISSION WASHINGTON. D. C. 20555
.s,. m f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 78 TO FACILITY OPERATING LI' CENSE NO. DPR-28 S d b,]ERMONT YANKEE. NUCLEAR POWER CORPORATION 4 g g.
p,
% f VERMONT YANKEE NUCLEAR POWER STATION
- c c ;
5 DOCKET NO. 50-271
~
.m
' Introduction
- 6 c.
-?
By letter dated February 22, 1983 the Vermont Yankee Nuclear Power Corporation submitted proposed. change No.111' to the Technical Specifications for the Vermont Yankee Nuclear Power Station.
The proposed change would permit the local power range monitors (LPRMs) to be disconnected during refueling outage work in order to preclude damage to the electrical connections.
Repair of such damage increases personnel radiation exposure.
The pre:ent Technical Specifications permit such disconnection when the mode switch is in the Shutdown or Refuel mode but not phen it is in the Startup
_ mode.
The latter mode is necessary to permit tly performance of refueling interlo,k check.
c Evaluation Disconnecting the LPRMs makes the average power range monitors (ARPMs) inoperable and thus not available to protect against power increase events in the core.
The APRM scram is set at 15 percent of full power when in the Refuel, Shutdown or Startup mode in order to protect against exceeding the safety limit of 25 percent of rated thermal power in the event of a reactivity l
insertion event.
Similar protection is provided by the intermediate range monitor (IRM) scram or by the source range monitor (SRM) scram.
Either of the latter scrams would act before the APRM scram by an amount which depends I
l on the rapidity with which the power is rising.
The revised Technical Specifications would require that both the IRM scram and l
the SRM scram (in the noncoincidence mode) be operable when the LPRMs are disconnected and the mode switch is in Startup.
Present Technical Specifications require only one of these scrams to be operable.
We conclude that the revised requirements offer the same level of protection as the present requirements and therefore, find the Technical Specification
~:
change acceptable.
A further requirement is that no more than two control rods may be withdrawn and that these may not be face adjacent or diagonal adjacent rods.
e
._-r_
7.
q r--_ _,
Environmental Consideration We have' determined.that the amendment does not authorize a change,"c's r*
-s in effluent types or, total amountstnor an increase.in power level and will'iiot' result *iririnfsignificant';en' ironmental impalt; HaiingMs" > "P.' ~ L;,
/
v made this determination, we have further concluded that the amendments -
involves an action which is' insignificant from the~ standpoint of-environmental impact' and, pursuant to.10 CFR 551.5(d)(4), that an environmental impact 1 statement, or negative declaration and environ -
mental impact appraisal. need not be prepared in connection with the' issuance of this amendment ~.
Concl us ion.. _
We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in t.he probability or consequences of an accident previously evaluated, does not create the possibility of an accident of a type different from any evaluated previously, and does not involve a significant reduction in a margin of safety, the amend ~ ment does not involve a significant hazards consideration,-(2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance w.ith the Commission's regulations and the
_ ~ issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated: April 11, 1983
~
Principal Contributor:
Walt Brooks 4
O e
h e
e