ML19318B984
| ML19318B984 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/23/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| TVA-SNP-TS-1, NUDOCS 8006300387 | |
| Download: ML19318B984 (11) | |
Text
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J 400 Chestnut Street Tower II June 23, 1980 TVA-SNP-TS-1 Mr. H. R. Denton, Director Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Denton:
In the Matter of
)
Docket No. 50-327 Tennessee Valley Authority
)
Reference:
Letter from L. M. Mills to H. R. Denton dated March 28,1980 (TVA-SNP-TS-1)
In the referenced letter, TVA requested an amendment to license DPR-77 to change several technical specifications for Sequoyah Nuclear Plant (SNP) unit 1.
During the review of these technical specification changes, NRC staff members in the standard technical specification group requested that TVA provide additional information regarding the changes to specifica-tion 2.2.1, " Reactor Trip System Instrumentation Setpoints," and specifica-tion 3.9.1, " Boron Concentration - Refueling." These changes were numbered 1 and 4, respectively, in the original request.
Enclosed for your review is the information requested (Enclosure 1).
A copy of the SNP Final Safety Analysis Report (FSAR) description of the P-8 reactor trip interlock in included to support the change to specification 2.2.1.
The description includes logic diagrams for derivation and application of the P-8 interlock.
A flow diagram (FSAR figure 9.3-14) for the Chemical and Volume Control System is included to support the change to specification 3.9.1.
Also included as Enclosure 2 are copies of the original change requests for specifications 2.2.1 and 3.9.1.
Very truly yours, TENNESSEE VALLEY AUTHORITY
),
L. M. Mills, Manager Nuclear Regulation and Safety Enclosures (10)
THIS DOCUMENT CONTAINS P00R QUALITY PAGES 80063003r9 P~'"~~~"
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e E!! CLOSURE 1 ADDITIONAL INFOR?tATION REGARDING SEQUOYAll NUCLEAR PLANT TECllNICAL SPECIFICATION CIIANGE TVA-SNP-TS-1 4
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Source range level trip block and high voltage cutoff are
(
)
always maintained when above the permissive F-10 level.
\\.j The intermediate range level trip and power-range (low setpoint) trip can only be blocked af ter satisfactory operation and permissive information are obtained from two of four power range channels. Individual blocking switches are provided so that the low-range power range trip and intermediate range trip can be independently blocked. These trips are automatically reactivated when any three of the four power range channels are below the permissive (P-10) Icvel, thus ensuring automatic activation to more restrictive trip protection.
The development of permissives P-6 and P-10 is shown on Figure 7.2-1, Sheet 4.
All of the permissiws are digital; they are derived f rom analog signals in the nuclear power range and intermediate range channels.
See Table 7.2-2 for the list of protection system interlocks.
2.
Blocks of Reactor Trips at Low Power Interlock P-7 blocks a reactor trip at low power (below approxi-mately 10 percent of full power) on a low reactor coolant flow or reactor coolant pump breaker open signal in more than one loop, reactor coolant pump undervoltage, reactor coolant p) pump underfrequency, pressurizer low pressure, pressurizer
(,
high water level or turbine trip signal.
See Figure 7.2-1, Sheets 6 and 16, for permissive applications. The block action (absence of P-7) occurs when three out of four power range neutron flux signals are below the setpoint in coincidence with two out of two turbine impulse chamber pressure signals below the setpoint (low plant load).
The P-8 interlock blocks a reactor trip when the plant is below approximately 50 percent of full power, on either a 2/3 low reactor coolant flow or a reactor coolant pump breaker open signal in any one loop. The block action (absence of
~
the P-8 interlock signal) occurs when three out of four neutron flux power range signals are below the setpoint. Thus, below the P-8 setpoint, the reactor will be allowed to operate with one inactive loop and trip will not occur until two loops are indicating low flow.
See Figure 7.2-1, Sheet 4, for derivation of P-8, and sheet 5 for applicable logic.
See Table 7.2-2 for the list of protection system blocks.
- 7. 2. L.1. 4.
Coolant Tcmperature Sensor Arrangement The hot and cold leg resistance temperature detectors are inserted into reactor coolant bypass loops. A bypass loop from upstream of the steam generator to downstream of the steam generator is p) used for the hot leg resistance temperature detectors and a bypass
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l;.:;q;n, SEQUOYAH NUCLEAR PLANT FINAL SAFETY
g-ENCLOSURE 2 ORIGINAL CIIANGES TO SEOUOYAli 1,'UCLFAR PLAI;T TECl!NICAL SPECIFICATIONS (TVA-SNP-TS-1)
M TABLE 2.2-1 (Continued)
S
.Q REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS
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[.FUNCTIONALUNIT TRIP SETPOINT ALLOWABLE VALUES z
Z ' 21.
Turbine' Impulse Chamber Pressure'-
< 10% Turbine Impulse 5 11% Turbine Impulse f(P-13) Input to Low Power Reactor Trips Pressure Equivalent Pressure Equivalent.
Block P-7
' 22.
Pouer Range Neutron Flux - (P-8) Input
< 35% of RATED
< 36% of RATED-to Low Reactor Coolant Loop Flow TilERMAL POWER TilERMAL POWER Reactor Trip
. 23.
Power Range Neutron Flux - (P-10) -
> 10% of RATED
> 9% of RATED-Enable block of Source, Intermediate, TilERMAL POWER Tf!ERMAL POWER and Power Range (low setpoint) reactor 4
Trips 24.
Reactor Trip P-4 Not Applicable Not Applicable NOTATION I
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NOTE 1:
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REFUELII;G OPEPdTIO? S -
SURVEILIA!!CE REOUIREME!;TS (Continued) 4.9.1.3-.One of the follouing valve combinations shall be verified closed under administrative control at least once per 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />s:
Conbination A Conbination B Combination C Combination D
- a. 1-81-536
~ a. 1-81-536
- a. 1-81-536
- n. 1-31-536
- b. 1-62-922
- b. 1-62-922
- b. 1-62-907
- b. 1-62-907
- c. 1-62-916
- c. 1-62-916
- c. 1-62-914
- c. 1-62-914
- d. 1-62-933 d. 1-62-94 0
- d. 1-62-921
- d. 1-62-921
- e. 1-62-696
- e. 1-62-933
- e. 1-62-940
- f. 1-62-929
- f. 1-62-696
- g. 1-62-932
- g. 1-62-929
- h. 1-FCV-62-128
- h. 1-62-932
- 1. 1-FCV-62-128 I
a SEQUOYAII -- UI;IT 1 3/4 9-la
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3/4.9 REFUELING OPERATIONS 3/4.9.1 BORON CONCENTRATION LIMITING CONDITION FOR OPERATION 3.9.1 With th~e reactor vessel head unbolted or removed, the boron concentration of all filled portions of the Reactor Coolant System and the refueling canal shall be maintained uniform and sufficient to ensure that the more restrictive of the following reactivity conditions is met:
a.
Either a K of 0.95 or less, which includes a 1% delta k/k conser-gff vative allowance for uncertainties, or b.
A baron concentration of greater than or equal to 2000 ppm, which includes a 50 ppm conservative allowance for uncertainties.
APPLICABILITY: MODE 6*
ACTION:
With the requirements of the above specification not satisfied, immediately suspend all operations involving CORE ALTERATIONS or positive reactivity changes and initiate and continue boration at greater than or equal to 10 gpm of a solution containing 20,000 ppm baron or its equivalent until K is eff reduced to less than or equal to 0.95 or the boron concentration is restored to greater than or equal to 2000 ppm, whichever is the more restrictive. The provisions of Specification 3.0.3 are not applicable.
SURVEILLANCE REOUIREMENTS 4.9.1.1 The more re crictive of the above two reactivity conditions shall be determined prior to:
Removing or unbolting the reactor vessel head, and a.
b.
Withdrawal of any full length control rod in excess of 3 feet from its fully inserted position within the reactor pressure vessel.
- 4. 9.1. 2 The boron concentration of the reactor coolant system and the refueling canal shall be determined by chemical analysis at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
"Ine reactor snall be maintained in MODE 6 whenever the reactor vessel head is unbolted or removed and fuel is -in the reactor vessel.
SEQUOYAH - UNIT 1 3/4 9-1 a
r -
F
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'
- 1.' "
1 ABLE_2. 2-1, PAGE 2-7 The reactor trip logic was modified at RC request.
However, the draft technical specifications were incorrectly prepared.
This change reflects the NRC approved reactor trip logic.
4.
SPECIFICATION 3.9.1, PAGE 3/4 9-1.
The present valve list does not allow for makeup to the Refueling !!ater Storage Tank during MODE 6.
The proposed change allows for makeup '.:hile still preventing an inadvertent dilution of the reactor coolant system.
4