ML20054A092
| ML20054A092 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 03/31/1982 |
| From: | PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20054A087 | List: |
| References | |
| NUDOCS 8204150278 | |
| Download: ML20054A092 (6) | |
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s Trojan Nuclear Plant Lynn Frank Docket 50-344 March 31, 1982 License NPF-1 LCA 85 Page 1 of 4 LICENSE CHANGE APPLICATION 85 The Technical Specification Limiting Condition for Operation 3.3.3.2 is revised as follows:
Existing Specification 3.3.3.2 The movable incore detection system shall be OPERABLE with:
a.
At least 75 percent of the detector thimbles, b.
A minimum of two detector thimbles per core quadrant, and c.
Sufficient movable detectors, drive, and readout equipment to map these thimbles.
I Proposed 3.3.3.2 The movable incore detection system shall be OPERABLE with:
a.
At least 75 percent of the detector thimbles for Applica-bility C and B, b.
At least 18 thimbles for quarter-core flux maps for I
Applicability A, i
c.
A minimum of two detector thimbles per core quadrant for Applicability C and B, and d.
Sufficient movable detectors, drive, and readout equipment i
to map these thimbles.
(NOTE: Applicability A, B, and C are shown on the attached page 3/4 3-37 of the Technical Specifications.)
l In addition, the following statement is added to the Bases for Technical Specification 3/4.3.3.2, Movable Incore Detectors:
N For the purpose of measuring F (z) or FaH, a full incore flux map is used. Quarter-core flux maps, as defined iny WCAP-8648, June 1976, may be used in recalibration of the excore axial flux of fset detection system.
Rev! sed Pages 3/4 3-33 and B 3/4 3-2 are attached.
REASON FOR CHANGE In November 1977 the h7C completed its review of the Westinghouse Electric Corporation topical report WCAP-8648 (nonproprietary), entitled "Excore Detector Recalibration Using Quarter-Core Flux Maps".
It was concluded that WCAP-8648 was acceptable for reference in license applications to 8204150278 820412 DR ADOCK 05000344 p
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Trojan Nuclear Plant Lynn Frank Docket 50-344 March 31, 1982 License NPF-1 LCA 85 Page 2 of 4
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I justify the technique of using quarter-core flux maps for calibration of power range excore detectors in Westinghouse reactors. The NRC letter which documented this evaluation is included in the attached WCAP-8648-A.
This License Change Application proposes to allow quarter-core flux mapping (QCFM) to be used at the Trojan Nuclear Plant for the recalibration of the excore axial flux offset detection system. The recalibration procedure using QCFM has a number of advantages over past procedures.
The time necessary for adequate data acquisition is cut approximately in half, yet the number of generated data points is significantly increased. Using QCFM for recalibration of the excore detectors permits the Plant to return to full power sooner and can potentially save 6 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of operation at a reduced power when compared to the current recalibration procedure.
SAFETY / ENVIRONMENTAL EVALUATION Discussion of Change This License Change Application proposes a revision to the Trojan Nuclear Plant Technical Specifications to allow quarter-core flux mapping in place of full-core flux mapping for recalibration of the axial flux offset detec-tion system. The basis for the suitability of this change is provided in WCAP-8648-A, "Excore Detector Recalibration Using Quarter-Core Flux Maps",
which incorporates the NRC Light Water Reactors Branch No. 1 evaluation j
concluding that the subject report is acceptable when referenced in utility l
applications to justify use of the quarter-core flux mapping technique for calibration of power range excore detectors in Westinghouse-designed reactors.
Quarter-core flux mapping (QCFM) work was conducted and evaluated at the Trojan Nuclear Plant. The results of QCFM presented in WCAP-8648-A show excellent agreement with the normal full-core flux maps for all power distribution parameters.
The advantage of QCFM over normal full-core flux maps is that it requires only approximately half the time or less to acquire the necessary data. Use of QCFM for recalibration of the excore axial flux offset detection system would result in a shorter time at reduced power.
The QCFM is a method which is especially useful for measuring the core power distribution during transient xenon conditions if time does not permit l
full-core mapping. QCFM requires three passes of the movable detector l
system (18 thimbles), with the measurement locations judiciously chosen so that when these measurements are reflected into a single quarter-core, i
a representative distribution of the typical assemblies is obtained.
The measurement sampling and distribution then approximate that used in a full-core flux map.
Proper thimble selection is recognized to be very important to insure the validity of the quarter-core flux map. WCAP-8648-A provides the thimble selection criteria and, in brief, the criteria are listed below in order of priority:
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e Trojan Nuclear Plant Lynn Frank Docket 50-344 March 31, 1982 License NPF-1 LCA 85 Page 3 of 4 a.
Af ter all selected thimbles are reflected into a single quarter-core, the center of every assembly with this equivalent quarter-core is within one assembly pitch of a movable detector measurement.
b.
When the selected thimbles are further reflected into a single eighth-core, the number of eighth-core symmetric pairs of measured thimbles should be minimized.
c.
The selected thimbles should be randomly distributed in the full-core pattern with measurements in u,'c y quad-r rant of the core.
Thimble measurement locations will be selected at the Trojan Nuclear Plant utilizing these criteria.
Actual comparisons of QCFM with full-core flux maps, as presented in Table 2-5 of WCAP-8648-A, shows that these two methods agreed within 1 percent of each other for four-loop plants. This shows that QCFM can be used to determine core average axial offset with a high degree of reliability and can thus be used for recalibration of the excore detec-tors in accordance with the procedure in WCAP-8648-A.
This proposal to utilize QCFM for recalibration of the excore axial flux offset detection system does not constitute an unreviewed safety question.
The attached WCAP-8648-A is applicable to the Trojan Nuclear Plant, and the use of QCFM has received prior review and acceptance by the NRC.
It is concluded that this revision does not involve a decrease in safety margins, and the health and safety of the public will not be endangered due to operation in this proposed manner.
Effect on the Technical Specifications and the Bases for the Technical Specifications The Technical Specifications and the Bases are affected as described above in the Description of Change.
No other changes are necessary.
l Effect on FSAR Flux mapping is described in Section 7.7.1.9.3, and quarter-core flux mapping should be included in this section. A revision to the FSAR to incorporate this change will be processed af ter approval of this License Change Application.
Environmental Effect The proposed change does not affect the environmental analyses in the FSAR, the Environmental Report or the final Environmental Impact Statement.
No unreviewed environmental question exists, and there is no significant adverse effect on the environment.
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Trojan Nuclear Plant Lynn Frank Docket 50-344 March 31, 1982 License NPF-1 LCA 85 Page 4 of 4 BASIS FOR DETERMINATION OF AMENDMENT CLASS This License Change Application has been determined to result in a Class III amendment in accordance with 10 CFR 170.22 since it involves a single issue and does not involve a significant hazard consideration. The fee for a Class III amendment is $4,000.
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o INSTRUMENTATION MOVABLE INCORE DETECTORS LIMITING CONDITION FOR OPERATION 3.3.3.2 The movable incore detection system shall be OPERABLE with:
a.
At least 75% of the detector thimbles for Applicability C and B,
b.
At least 18 thimbles for quarter-core flux maps for Applicability A, c.
A minimum of 2 detector thimbles per core quadrant for Applicability C and B, and d.
Sufficient movable detectors, drive, and readout equipment to map these thimbles.
APPLICABILITY:
When the movable incore detection system is used for:
A.
Recalibration of the axial flux offset detection system, B.
Monitoring the QUADRANT POWER TILT RATIO, or N
C.
Measurement of F and Fg (Z).
3H ACTION:
With the movable incore detection system inoperable, do not use the system for the above applicable monitoring or calibration functions. The provisions of Specifications 3.0.3 and 3.0.4 are not applicable.
SURVEILLANCE REQUIREMENTS 4.3.3.2 The incore movable detection system shall be demonstrated OPERABLE by normalizing each detector output to be used within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to its use when required for:
a.
Recalibration of the excore axial flux offset detection system, or b.
Monitoring the QUADRANT POWER TILT RATIO, or N
c.
Measurement of F and Fq (Z).
6H TROJAN-UNIT 1 3/4 3-37
e INSTRUMENTATION RASES RADI ATION MONITORING INSTRUMENTATION (Continued) by the individual channels and 2) the alarm or automatic action is initiated when the radiation level trip setpoint is exceeded.
3/4.3.3.2 MOVABLE INCORE DETECTORS The OPERABILITY of the movable incore detectors with the specified minimum complement of equipment ensures that the measurements obtained from use of this system accurately represent the spatial neutron flux distribution of the reactor core.
For the purpose of measuring F (Z) or F H, a full incore flux map g
is used. Quarter-core flux maps, as defined in WCAP-8648, June 1976, may be used in recalibration of the excore axial flux offset detection system.
3/4.3.3.3 SEISMIC INSTRUMENTATION The OPERABILITY of the seismic instrumentation ensures that suffi-cient capability is available to promptly determine the magnitude of a seismic event and evaluate the response of those features important to safety. This capability is required to permit comparison of the measured response to that used in the design basis for the facility and is con-sistent with the recommendations of Regulatory Guide 1.12, " Instrumentation for Earthquakes."
3/4.3.3.4 METEOROLOGICAL INSTRUMENTATION The OPERABILITY of the meteorological instrumentation ensures that sufficient meteorological data is available for estimating potential radiation doses to the public as a result of routine or accidental release of radioactive materials to the atmosphere. This capability is required to evaluate the need for initiating protective measures to protect the health and safety of the public and is consistent with the recommendations of Regulatory Guide 1.23, "0nsite Meteorological Programs."
3/4.3.3.5 REMOTE SHUTDOWN INSTRUMENTATION The OPERABILITY of the remote shutdown instrumentation ensures that sufficient capability is available to permit shutdown and main-tenance of HOT STANDBY of the facility from locations outside of the control room. This capability is reouired in the event control room habitability is lost and is consistent with General Design Criteria 19 of 10 CFR 50.
TROJAN-UNIT 1 8 3/4 3-2