BVY 07-052, Revision of Technical Specification Bases Pages
| ML072190205 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/31/2007 |
| From: | Ted Sullivan Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BVY 07-052 | |
| Download: ML072190205 (8) | |
Text
Entergy Nuclear Operations, Inc.
Vermont Yankee P.O. Box 0500
--En erg 185 Old Ferry Road Brattleboro, VT 05302-0500 Tel 802 257 5271 July 31, 2007 BVY 07-052 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Revision of Technical Specification Bases Pages
Dear Sir or Madam,
This letter provides revised Technical Specification (TS) Bases pages.
Bases pages 227 and 227a have been revised to clarify the Bases for TS Section 3.11, "Reactor Fuel Assemblies," due to changes in reactor core analytical capability.
These changes to the TS Bases have been determined to not require prior NRC approval in accordance with 10CFR50.59.
For your information and records, a marked-up copy of the Bases pages as well as a re-typed copy are included as Attachments 1 and 2.
Should you have any questions concerning this matter, please contact Mr. David Mannai at (802) 258-5422.
Sincerely, Site Vic President Vermont Yankee Nuclear Power Station Attachments (2) cc listing (next page)
A boI
BVY 07-052 Page 2 of 2 cc:
Mr. Samuel J. Collins Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406-1415 Mr. James Kim, Project Manager Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop O-8C2A Washington, DC 20555 USNRC Resident Inspector Entergy Nuclear Vermont Yankee, LLC 320 Governor Hunt Road Vernon, Vermont 05354 Mr. David O'Brien, Commissioner VT Department of Public Service 112 State Street - Drawer 20 Montpelier, Vermont 05620-2601
BVY 07-052 Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Revision of Technical Specification Bases Pages Marked-up Version of Bases Pages
I I VYNPS BASES 3.11 FUEL RODS A.
Average Planar Linear Heat Generation Rate (APLHGR)
Refer to the appropriate topical reports listed in Specification 6.6.C for analyses methods.
(Note:
All exposure increments in this Technical Specification section are expressed in terms of megawatt-days per short ton.)
The MAPLHGR reduction factor for single recirculation loop operabion is based on the assumption that the coastdown flow from the unbroken recirculation loop would not be available during a postulated large break in the active recirculation loop.
See Core Operating Limits Report for the cycle-specific reduction factor.
Flow dep ndent MAPLHGR limits, MAPFAC(F),
were designed to assure adhere to all fuel thermal-mechan cal design basey.
The same tran~ent events us to support tSr MCPR(F) operating limits were an 'yzed, and the/ esulting ove powers were stat tically evaluate as efunction of te initial and imum core flos.
From the bound' g overpowers" e MAPFAC(F} I ts were* derive such that the pe transient *R would not eceed fuel mech cal limits.
The ow-dependenPLHGR limits are cycle-indep dent and are spec 'ied in terms o2multipliers, FAC(F), to be pplied to the ra MAPLHGR valu wer-dependent LHGR limits, ressed in terms f a MAPLHGR multiplier, AC(P), are sub ituted to assure dherenceto th fuel thermal mech ipie enterline me ing of fuel and p stic strain of he cladding are onsidered in de rmining the powe ependent limit. Gener y, the limitin criterion is inc ient centerlin melting. The poer-dependent AC!(P) mult iers were gen ated usinng the se database as ed to de rmine the MCPR tiplier (IKp).
propriate MAP C(P) multiplie(
e selected base on plant-speci c transient ana ses with suit ae margin to assur applicability future reloads. These limits ~.e derived to as e that the pe transient MAPLH for any tran ent is not increas above the fuel denln bhn An valm Fz B.
Linear Heat Generation Rate (LHGR)
Refer to the appropriate topical reports listed in Specification 6.6.C for analyses methods.
i Power §nd flow ý6pendent L limits implemente ng LHGRFAC mult)pliers the standa LHGR 1
- a.
The LRAC multiplier are idefitical t6 the MAPFAC multipDl s.
C.
Minimum Critical Power Ratio (MCPR)
Operating Limit MCPR
- 1.
The MCPR operating limit is a cycle-dependent parameter which can be determined for a number of different combinations of operating modes, initial conditions, and cycle exposures in order to provide reasonable assurance against exceeding the Fuel Cladding Integrity Safety Limit (FCISL) for potential abnormal occurrences.
The MCPR operating limits are justified by the analyses, the results of which are presented in the current cycle's Supplemental Reload Amendment No. a4, 4-7,
-4, 64, #4, 45, a4O,.161, a5, B-.
99 56, a-7-1, 219 227
Insert I APLHGR is the average LHGR of all the fuel rods in a fuel assembly at any axial location. APLHGR limits ensure that the peak cladding temperature (PCT) during a design basis loss-of-coolant accident (LOCA) does not exceed 22007F. LOCA analyses are performed to verify this.
APLHGR limits are specified in the cycle-specific COLR.
Insert 2 LHGR is the linear heat generation rate of a fuel rod at a given nodal plane in a bundle.
LHGR limits are bundle type dependent and monitored to assure all mechanical design requirements are met.
Flow dependent LHGR limits were designed to assure adherence to all fuel thermal-mechanical design bases. The same transient events used to support the MCPR(F) operating limits were analyzed, and the resulting overpowers were statistically evaluated as a function of the initial and maximum core flow. From the bounding overpowers, the LHGRFAC(F) limits were derived such that the peak transient LHGR would not exceed fuel mechanical limits. The flow-dependent LHGR limits are cycle-independent and are specified in terms of multipliers, LHGRFAC(F), to be applied to the rated LHGR values.
Power-dependent LHGR limits, expressed in terms of a LHGR multiplier, LHGRFAC(P), are applied to assure adherence to the fuel thermal-mechanical design bases. Both incipient centerline melting of fuel and plastic strain of the cladding are considered in determining the power dependent LHGR limit. The power-dependent LHGRFAC(P) multipliers were generated using the same database as used to determine the MCPR multiplier (Kp). Appropriate LHGRFAC(P) multipliers are selected based on plant-specific transient analyses with suitable margin to assure applicability to future reloads. These limits are derived to assure that the peak transient LHGR for any transient is not increased above the fuel design bases values.
The LHGRFAC multipliers also provide adequate protection for the off-rated LOCA conditions since a constant local peaking factor is used in the LOCA evaluation.
LHGR limits are specified in the cycle-specific COLR.
A
BVY 07-052 Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Revision of Technical Specification Bases Pages Re-typed Version of Bases Pages
VYNPS BASES:
3.11 FUEL RODS A.
Average Planar Linear Heat Generation Rate (APLHGR)
Refer to the appropriate topical reports listed in Specification 6.6.C for analyses methods.
(Note:
All exposure increments in this Technical Specification section are expressed in terms of megawatt-days per short ton.)
The MAPLHGR reduction factor for single recirculation loop operation is based on the assumption that the coastdown flow from the unbroken recirculation loop would not be available during a postulated large break in the active recirculation loop.
See Core Operating Limits Report for the cycle-specific reduction factor.
APLHGR is the average LHGR of all the fuel rods in a fuel assembly at any axial location.
APLHGR limits ensure that the peak cladding temperature (PCT) during a design basis loss-of-coolant accident (LOCA) does not exceed 22001F.
LOCA analyses are performed to verify this.
APLHGR limits are specified in the cycle-specific COLR.
B.
Linear Heat Generation Rate (LHGR)
Refer to the appropriate topical reports listed in Specification 6.6.C for analyses methods.
LHGR is the linear heat generation rate of a fuel rod at a given nodal plane in a bundle.
LHGR limits are bundle type dependent and monitored to assure all mechanical design requirements are met.
Flow dependent LHGR limits were designed to assure adherence to all fuel thermal-mechanical design bases.
The same transient events used to support the MCPR(F) operating limits were analyzed, and the resulting overpowers were statistically evaluated as a function of the initial and maximum core flow.
From the bounding overpowers, the LHGRFAC(F)limits were derived such that peak transient LHGR would not exceed fuel mechanical limits.
The flow-dependent LHGR limits are cycle-independent and are specified in terms of multipliers, LHGRFAC(F),
to be applied to the rated LHGR values.
Power-dependent LHGR limits, expressed in terms of a LHGR multiplier, LHGRFAC(P),
are applied to assure adherence to the fuel thermal-mechanical design bases.
Both incipient centerline melting of fuel and plastic strain of the cladding are considered in determining the power dependent LHGR limit.
The power-dependent LHGRFAC(P) multipliers were generated using the same database as used to determine the MCPR multiplier (Kp).
Appropriate LHGRFAC(P) multipliers are selected based on plant-specific transient analyses with suitable margin to assure applicability to future reloads.
These limits are derived to assure that the peak transient LHGR for any transient is not increased above the fuel design bases values.
The LHGRFAC multipliers also provide adequate protection for the off-rated LOCA conditions since a constant local peaking factor is used in the LOCA evaluation.
LHGR limits are specified in the cycle-specific COLR.
Amendment No.
4-, 4-4, 4-G, 4_,
-94, -9&,
4G0, 44-6-,
4-54, ];;'Y99 55, 44-l, 4-9 227 BVY 07-052
4 4
t VYNPS BASES:
3.11 FUEL RODS (Continued)
C.
Minimum Critical Power Ratio (MCPR)
Operating Limit MCPR
- 1. The MCPR operating limit is a cycle-dependent parameter which can be determined for a number of different combinations of operating modes, initial conditions, and cycle exposures in order to provide reasonable assurance against exceeding the Fuel Cladding Integrity Safety Limit (FCISL) for potential abnormal occurrences.
The MCPR operating limits are justified by the analyses, the results of which are presented in the current cycle's Supplemental Reload Licensing Report.
Refer to the appropriate topical reports listed in Specification 6.6.C for analysis methods.
The increase in MCPR operating limits for single loop operation accounts for increased core flow measurement and TIP reading uncertainties.
Flow-dependent MCPR limits, MCPR(F),
are necessary to assure that the Safety Limit MCPR (SLMCPR) is not violated during recirculation flow increase events.
The design basis flow increase event is a slow (maximum two pump runout rate of 1%/second) recirculation flow increase event which is not terminated by scram, but which stabilizes at a new core power corresponding to the maximum possible core flow.
Flow runout events were analyzed along a constant xenon, constant feedwater temperature flow control line assuming a quasi steady-state plant heat balance.
The ARTS-based MCPR(F) limit is specified as an absolute value and is cycle-independent.
The operating limit is based on the maximum core flow limiter setting of 109.5% in the Recirculation Flow Control System.
Above the power at which the scram is bypassed (Pbypass),
bounding power-dependent trend functions have been developed.
This trend function, Kp, is used as multiplier to the rated MCPR operating limits to obtain the power-dependent MCPR limits, MCPR(P).
Below the power at which the scram is automatically bypassed (Below Pbypass),
the MCPR(P) limits are actual absolute Operating Limit MCPR (OLMCPR) values, rather than multipliers on the rated power OLMCPR.
Amendment No.
2-1, BVY 07-052 227a