ML17290A302
| ML17290A302 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 05/10/1993 |
| From: | WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | |
| Shared Package | |
| ML17290A301 | List: |
| References | |
| NUDOCS 9305180258 | |
| Download: ML17290A302 (35) | |
Text
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POWER OISTRIBUTION LIMITS 3/4. 2.6 POWER/FLOW INSTABILITY LIMITING CONOITION FOR OPERATION 3.2.6 Operation with THERMAL POWER/core flow conditions which lay in Region A
of Figure 3.2.6-1 is prohibited.
APPLICABILITY:
OPERATIONAL CONDITION 1, when THERMAL POWER is greater than
~TE E
io core f'low.
ACTION:
With TH RMAL POWER/core flow conditions which lay in Region A of Figure 3.2.6-E, then as soon as practical, but.in all cases within 15 minutes, initiate a MANUAL SCRAM.
SURVE<L~ ANC: RcOUIREMENvS 4.2.6 The THERMAL POWER/core flow conditions shall be ver i ied to lay outside Region A of Figure 3.2.6-1 once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when operating in the region of APPLICABILITY.
WASHINGTON NUCLEAR - UNIT 2 3/4 2-5 Amencment No.
'dASHHGTOH NUCLEAR - UNji 2 3/4 2-6 ga ruse~
Amendment Ho. 94
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3/4. 2 POWER OISTRIBUTIOH LIMiTS 3/4. 2.7 STABILITY MOHITORIHG - I'R LOOP OPERATION LIMITIHG COHOITION FOR OPERATION 3.2.7 The stability monitoring system shall be operable" and the decay ratio of the neutron sigrals shall be less than0.75 when aperating in the region of APPLICABILITY.
APPLICABILITY:
OPERATIONAL COHOITION 1, with two recirculation loops in operat>on and THERMAL POWER/core flow conditions which lay in Region C of Figure 3. 2. 7-1.
RCTIOM:
a.
With decay ratios of anv two (2) neutron signals greater than ~ or with two (2) consecutive decay ratios on any single neutron signal greater than 0c
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As soon as practical, but in all cases within 15 minu es, initiate action D,q 5 to reduce the decay ratio by either decreasing TH RMAL POWER with control rod insertion or increasing core flow with recirculation flow can ral valve manipulation.
The starting ar shifting of a recirculation pump fcr the purpose of decreasing decay ratio is specifically prahibited.
b.
With the stability monitoring sys em incperable and when operating in the region of APPLICABiLITY:
As soon as practical, but in all cases within 15 minutes, initiate ac.ion to exit the region of <PPLICABILITY by either decreasing THERMAL POWER with control ro" inse"-.ion or increasing car o flow with recircula=ion flow control valve manipulation.
The starting or shifting of a recirculation pump fcr the purpose of exiting the region of APP CABiLITY when the staoility monitoring sys em is inoperable is specifically prohibited.
Exi the region of APPL.CABiLiTY within one (1) hour.
SURVEiLLAHCE REQUIREMENTS 4.2.7.1 The provisions of Specification 4.0.4 are nct applicable.
4.2.7.2 The s ability monitoring system shall be demonstrated operable" within one (1) hcur prior to entry into the region of APPLICABILITY.
4.2.7.3 Oecay ratio and peak-to-peak noise values calculated by the staoility monitoring system shall be monitored when operating in the region of APPL'ABILITY.
"Ver ify that the stability monitoring sys em data acquisition and calculational modules are functioning, and that displayed values of signal decay ratio and peak-to-peak noise are being updated.
Oetec.or levels A and C (or B and 0) of one LPRM 's'tring in'each of the"nine core regions "('a"total '
oi 18'PRM detectors) shall be manitored.
A minimum of four (4)
APR4ls shall also be monitored.
WASHIHGTOH NUCLEAR - UNIT 2 3/4 2-7 Amencment Ho. -~
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(45.0F,47.1 P) 10 0
20 30 40 50 Core Flow (% Rated)
Operating Region Umits of Specification 3.2.7 Figure 3.2.7-1 60 70
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3/4. 2 POWER OESTRIBUTEOH LIMITS 3/4 2 8 STABELrTY MONITORING SINGLE LOOP OPERATEON LIMETIHG CONOETIOH FOR OPERATEOH 3.2.8 The stability monitoring system shall be operable" and the decay ratio of the neutron signals shall be less than0.75 when operating in the region of APPLICABILITY.
APPLICABILITY:
OPERATIONAL CONOITION 1, with one recirculation loop in operation and THERMAL POWER/core flow conditions which lay in Region C of Figure 3.2.8"1.
ACTION:
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With decay ratios of any two (2) neutron signals greater than ~ or with two (2) consecutive decay'ratios on any single neutron signal greater an As soon as practical, but in all cases within 15 minutes, initiate action to reduce the decay ratio by either decreasing THERMAL POWER with control rod inser ion or increasing core flow with recirculation flow control valve-manipulation.
The s arting or shifting of a recirculation pumo for the purpose of decreasing decay ratio is specifically prohibited.
b.
With he stability monitoring system inoperable and when operating in the region of APPLICABILITY:
As soon as prac ical, but in all cases within 15 minutes, initiate ac ion to exit the region of APPLICABILITY by decreasing THERMAL POWER with control rod insertion.
Exit the region of APPLICABILITYwi hin one (i) hour.
SURVE Ll"ANCE REQUIREMENTS 4.2.8.
The provisions of Specification 4.0.4 are no applicable.
4.2.8.2 The s ability monitoring system shall be demonstrated operable" within one (1) hour 'prior to entry into the region of APPLICABILiTY...
4.2.8.3 Oecay ratio and peak-to-peak noise values calculated by the s=ability monitoring system shall be monitored when operating in the region of APP LECABILiTY.
"Ver ify that the stability monitoring sys em data acquisi ion and calculational modules are functioning, and that displayed values of signal decay ratio and peak-to-peak noise are being updated.
Oetec or levels A and C (or B and 0) of one LPRM string in each of the nine core regions (a total of 18 LPRM detectors) shall be monitored.
A minimum of four (4} APRMs shall also be monitor ed.
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(39.0F,43.6P) 100% Rod Line (45.0F,57.2P) 10 0
20 30 40 50 Core Flow (% Rated)
Operating Region Limits of Specification 3.2.8 Figure 3.2.8-1 60 70
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Operating Region Urnits of Specification 3.4.1.1 Figure 3.4.1.1-1 60 70
POWER DISTRIBUTION LIMITS BASES slightly increasing the time required for the normal scram to suppress the f1 ux.
3/4.2.4 LINEAR HEAT GENERATION RATE This specification assures that the Linear Heat Generation Rate (LHGR) in any rod is less than the design linear heat generation even if fuel pellet
. densification is postulated.
3/4. 2. 6 POWER/FLOW INSTABILITY At the high power/low flow corner of the operating
- domain, a small probability of limit cycle neutron flux oscillations exists depending on combinations of operating conditions (e. g.,
power-shape, bundle power, and bundle flow).
In February,
In this SIL, the power/flow map was divided into several regions of varying concern.
It also discussed the objectives and philosophy of "detect and suppress,"
coining the phrase.
Siemens The&% topical report for COTRAN (XN-NF-691P) discusses boiling insta-bility.
The SER written on this topical (dated May 10, 1984) interprets the topical to require that the detect-and-suppress surveillance be used in regions which have code calculated decay ratios0. 75 or greater and that operation is.
forbidden in regions having calculated decay ratios of0.9 and greater. (>>
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The NRC Generic Letter 86-02 addre'ssed both GE and ANF (then EXXON) stability calculation methodology and stated that due to uncertainties, General Design Criteria 10 and 12 could not be met using analytic procedures on a BWR 5 design.
The letter espoused GE SIL 380 and stated that General Design Criteria 10 and,l2 could be met by imposing the SIL 380 recommendations in operating regions of potential instability.
The NRC concluded that regions of potential instability constituted calculated decay ratios of0.8 and greater by the GE methodology and0.75 and greater by the EXXON methodology.
icated on the SII 380 endorsement, WNP-2 has divided the power/
w-map on the llowing boundary lines:
l.
2 3.
5.
80K rod 45K core flow, '
100'od line Natural Circulation flo e
Minimum Forced Circ son
<(
gtP/GC6 ormal recircu'lation lineup.
This division orms to the SIL 380 recomme ions.
For LCO 3.2.6, the region of conc (Region A) is bounded by the more cons tive of either the 100K rodli or a line defining a calculated decay ratio of the natural circul on flow line, and the 45K core flow line.
Calculated dec atios ou de Region A must be less than 0.9.
Operation in the region between two WASHINGTON NUCLEAR - UNIT 2 B 3/4 2-5 Amendment No.
84
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POWER DISTRIBUTION LIMITS BASES f ow lines and above defining a calculated deca boiling instabil ive of e
00X rodline or a line "
ss or "dden-d to the potential for 3/4.2.7 STABILITY MONITORING - TWO LOOP OPERATION At the high power/low flow corner of the operating
- domain, a
ability of limit cycle neutron flux osci llations exists depending tions of operating conditions (e. g., rod patterns, power shape).
assurance that neutron flux limit cycle oscillations are detected
- pressed, APRH and LPRH neutron flux signal decay ratios should be
'while operating in this region.
small prob-on combina-To provide and sup-monitored Stability tests at operating BWRs were reviewed to determine a generic region of the power/flow map in which surveillance of neutron flux noise levels should be performed.
A conservative decay ratio of 0.75 was chosen as the basis for determining the generic region for surveillance to account for the plant to plant variability of decay ratio with core and fuel designs.
This generic region has been determined to correspond to a core flow of less than or equal to 45X of rated core flow and a thermal power greater than that corresponding to the~ rodline.
7c5 Stability monitoring is performed utilizing the ANNA system.
The system shall be used to monitor APRH and LPRH signal decay ratio and peak-to-peak noise values when operating in the region of concern.
A minimum number of LPRM and APRM signals are required to be monitored in order to assure that both global (in-phase) and regional (out-of-phase) oscillations are detectable.
Decay ratios are calculated from 30 seconds worth of data at a sample rate of 10 samples/second.
This sample interval results in some inaccuracy in the decay ratio calculation, but provides rapid update in decay ratio data.
A decay ratio of 0.75 is selected as a decay ratio limit for operator response such that. sufficient margin to an instability occurrence is maintained.
When operating in the region of applicability, decay ratio and peak-to-peak information shall be continuously calculated and displayed.
A surveil'lance requirement to continuously monitor decay ratio and peak-to-peak noise val'ues ensures rapid response such that changes in core conditions do not result in approaching a
point of instability.
3/4.2.8 STABILITY MONITORING " SINGLE LOOP OPERATION The basis for stability monitoring during single loop operation is consistent with that given above for two loop operation.
The smaller size of the region of allowable operation, Region C, is due to a limit on the allowed flow above the X rodline.
When operating above the 4
- rodline in single loop operation, the core flow is required to be greater an 39X.
WASHINGTON NUCLEAR " UNIT 2 B 3/4 2-6 Amendment No.
84
INSERT A The Siemens stability code STAIF (a frequency domain code) is also used to provide confirmation of the regions.
Siemens has committed to use the STAIF code in addition to COTRAN,and used the more:,conservative of the two results in a letter to the NRC (RAC:92: 145, RA Copeland (SPC) to LE Phillips (NRC),
"SPC Stability Evaluations,"
dated December 2, 1992).
0 EyL~
4
INSERT B
Predicated on the SIL 380 endorsement and Siemens calculations with both COTRAN and STAIF, WNP-2 has divided the power/flow map on the following boundary lines 1.
2.
3.
4.
5.
6.
75% rod line 45% core flow 77% rod line from natural circulation to 91% rod line at 35% core flow 100% rod line Natural Circulation flow line Minimum Forced Circulation for normal recirculation lineup This division conforms to the SIL 380 recommendations except that Region A has been expanded between natural circulation and 35% core flow.
For LCO 3.2.6, the region of concern (Region A) is bounded by the more conservative of either the 100% rod line or a line defining a calculated decay ratio of 0.9, the natural circulation flow line, and the 45% core flow line.
Operation between the two flow lines and the more conservative of either the 100% rod line or a line defining a calculated decay ratio of 0.9 is forbidden due to the potential for boiling instabilities.
Recent calculations by Siemens show that although COTRAN calculates the 0.9 decay ratio line to be above the 100% rod line, the STAIF stability code calculates the 0.9 decay ratio as below the 100% rod line at core flows less than 30%.
Therefore, Region A has been expanded.
Region A is. above the line between a point at 36% power and 23.8% flow and a point at 50.3% power and 35%
flow and for core flows greater than 35% the region is bounded by the 91% rod line.
Region C is bounded by the 75% rod line.
t J
A'te 2C." 3 April 20, 1993 RAC:93:049 Mr. David Whitcomb Washington Public Power Supply System P. O. Box 968 Richland, Washington 99352
Dear Mr. Whitcomb:
Affidavitfor SPC Proprietary Letter
Reference:
Letter, U. Fresk (SPC) to R. A. Vopalensky (WPPSS), "Summary of Stability Ucensing Calculations in Support of WNP-2 Cycle 9," April 2, 1993, SP CWP-93%46.
In our telephone conversation yesterday, you requested an affidavit to support the submittal of the referenced proprietary letter to the NRC. This affidavit is needed to allow the NRC to withhold the letter from public distribution. When transmitting the letter and affidavit, please include the following paragraph.
Siemens Power Corporation considers the information contained in the letter of U. Fresk to R. A. Vopalensky, dated April 2, 1993, SPCWP-93-046, to be proprietary.
In accordance with the requirements of 10 CFR 2.790(b), an affidavit is enclosed to support withholding this letter from public disclosure.
If you have any questions, or if I can be of additional help, please contact me.
Very truly yours, R. A. Copeland, Manager Product Licensing
/smg Attachment cc:
Ms. Y. U. Fresk (SPC)
Mr. R. A. Vopalerisky (WPPSS)
~
Siemens Power Corporation Nuclear Division - Engineering and Manufacturing Facility 2101 Morn Rapids Road, PO Box 130 Richland, WA 993524130 Tel: (509) 375-8100 Fax: (509) 375-8402
AFFIDAVIT STATE OF WASHINGTON
)
)
COUNTY OF BENTON
)
ss.
I, R. A. Copeland being duly sworn, hereby say and depose:
I am Manager, Product Licensing, for Siemens Power Corporation ("SPC"),
and as such I am authorized to execute this Affidavit.
2.
I am familiar with SPC's detailed document control system and policies which govern the protection and control of information.
3.
I am familiar with the letter from Y. U. Fresk (SPC) to R. A. Vopalensky dated April 2, 1993, SPCWP-93-046 entitled "Summary of Stability Licensing Calculations in Support of WNP-2 Cycle 9," referred to as "Document." Information contained in this Document has been classified by SPC as proprietary in accordance with the control system and policies established by SPC for the control and protection of information.
4.
The Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by SPC and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in the Document as proprietary and confidential.
5.
The Document has been made available to the U.S. Nuclear Regulatory Commission in confidence, with the request that the information contained in the Document will not be disclosed or divulged.
1 I
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t
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6.
The Document contains information which is vital to a competitive advantage of SPC and would be helpful to competitors of SPC when competing with SPC.
7.
The information contained in the Document is considered to be proprietary by SPC because it reveals certain distinguishing aspects of SPC licensing methodology which secure competitive advantage to SPC for fuel design optimization and marketability, and includes information utilized by SPC in its business which affords SPC an opportunity to obtain a competitive advantage over its competitors who do not or may not know or use the information contained in the Document.
8.
The disclosure of the proprietary information contained in the Document to a competitor would permit the competitor to reduce its expenditure of money and manpower and to improve its competitive position by giving it valuable insights into SPC licensing methodology and would result in substantial harm to the competitive position of SPC.
9.
The Document contains proprietary information which is held in confidence by SPC and is not available in public sources.
10.
In accordance with SPC's policies governing the protection and control of information, proprietary information contained in the Document has been made available, on a limited basis, to others outside SPC only as required and under suitable agreement providing for nondisclosure and limited use of the information.
11.
SPC policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.
12.
Information in this Document provides insight into SPC licensing methodology developed by SPC.
SPC has invested significant resources in developing the methodology as well as the strategy for this application.
Assuming a competitor had available the same background data and incentives as SPC, the competitor might, at a minimum, develop the information for the same expenditure of manpower and money as SPC.
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THATthe statements made hereinabove are, to the best of my knowledge, information, and belief, truthful and complete.
FURTHER AFFIANTSAYETH NOT.
SUBSCRIBED before me this >
day of
, 1993.
Sissan" K.. QiCoy "NOTHER~,Pt)BI'IC, STATE OF WAS GTON MY COI'v'fvti5~SION EXPIRES:
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