ML19274D252
| ML19274D252 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/03/1979 |
| From: | Conner E Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC-46174, NUDOCS 7901160396 | |
| Download: ML19274D252 (14) | |
Text
/
S UNITED STATES 37 NUCLEAR REGULATORY COMMisslON j
WASHINGTON, D. C. 20555
~%,[ /
January 3, 1979 Docket No. 50-336 LICENSEE: NORTHEAST NUCLEAR ENERGY COMPANY (NNECO)
FACILITY: MILLSTONE UNIT NO. 2 (M-2)
SUBJECT:
SUMMARY
OF MEETING HELD ON NOVEMBER 21, 1978 TO DISCUSS THE STRETCH POWER PROGRAM FOR MILLSTONE UNIT NO. 2 The meeting was held at the Comission's offices in Bethesda, Maryland.
A list of attendees is given in Enclosure 1.
Introduction By letter dated November 1,1978, NNECO notified the NRC of their intention to request an amendment for Cycle 3 operation of M-2 at the stretch power level of 2700 MWt. In a second letter dated November 8,1978, NNECO provided a system description for a Reactor Protection System (RPS) modification necessary to reach 2700 MWt.
This modification would replace the steam generator differential pressure.(Ap) signal with a Reactor Coolant Pump Speed Sensing System (RCPSSS) signal for the loss of four pump flow RPS trip.
The licensee requested the meetireg to discuss the staff review and develop an acceptable schedule. The meeting agenda is shown in Enclosure 2.
Sumary After opening remarks by the NRC (Conner) including passing out the Tentative Stretch Pcwer Review Schedule (Enclosure 3) and a request from NNECO (Kacich) to postpone scheduled discussion until the end of tna meeting, the licensee (Hart) gave the stretch power goals. Increasing the M-2 power from 2560 MWt to 2700 MWt will increase electrical production by about 40 MWe. This will be worth some 54,000,000 per year to the utility.
79011603'l6
Northeast Nuclear Energy Company In the environmental consideration presenta tion, NNECO (Kacich) pointed out that the Environmental Report (ER) and Final Environmental Statement (FES) encompassed plant operation at 2700 MWt in nearly every regard, that the radiological consequences of all postulated accidents were evaluated for 2700 MWt, and that the estim-ated release of radioactive materials from the radioactive waste systems were determined for a power level of 2700 MWt. Data was presented to show that the 5.5'.' increase in power level should not bring the average temperature rise across the condenser to the 23 F value assumed in the ER and FES.
In their radiological considerations discussion, NNECO (Kacich) identified the FSAR accidents previously analyzed acceptable at 2700 MWt as Fuel Handling, Hydrogen Purge, Waste Gas Decay, Tank Rupture and LOCA. The accidents not analyzed at 2700 MWt are Steam Generator Tube Rupture, Control Rod Ejection, Main Steam Line Break, and Seized Rotor Incidents. These previously un-analyzed (at 2700 MWt) postulated accidents are currently being reanalyzed.
The next presentation was on the CEA guide tube wear problem. NNECO (Harris) passed out Enclosures 4 and 5 showing their plan to place 44 fuel assemblies with reduced guide tube flow in the core for Cycle 3.
Only 4 of these reduced-flow fuel assemblies will be positioned under CEAs because of fuel loading restrictions (core loading is already set). They plan to request an increase in the control rod drop time from 2.75 to 3.1 seconds.
The staff (Johnson) questioned the affect that the 44 reduced guide tube flow fuel assemblies would have on the apptitude of the CEA vibration in the sleeved fuel assemblies as their flow is increased. This question was left to be answered as a part of the Cycle 3 evaluation.
In regard to the RCPSSS, NNECO (Roby) pointed out that this modi-fication is not absolutely necessary for stretch power operation, but will provide increased margin on the DNB limits. The modification will replace the ap signal for the loss of total flow (4 RCP trip),
only. The speed sensing design is a best choice according to CE.
The design is similar to a small part of the Arkansas 2 RPS. The setpoint will be calculated in the Cycle 3 reanalysis, but will not be a variable during operation. Enclosures 6, 7 and 8 were passed out and discussed. The flow detector will be of a proximity type.
A spare RPS channel will be used for this system's connection into the RPS. The licensee stated that the RCPSSS could result in a 10%
improvement in DNBR.
NNECO (Roby) said that the RCPSSS would be fully qualified to IEEE. 323 (1971). Discussion about the worst containment environment and equipment aging followed. The staff (Burdain) is to respond to the licensee (Roby) in regard to the acceptability of the 1971 version of IEEE 323. NNECO (Kacich) said that the request for an amendment with the appropriate TS would be submitted in early January. The staff (Brinkman) pointed out that the TS should include a once-per-
2rtheast fluclear Energy Ccmpany shift surveillance requirement to confim the ficw-verses-speed relationship.
S In the discussion of the dycle 3 reload engineering and Stretch Power safety analysis, the staff (Reid) questioned the affect of not approving the stretch power request at the time the reload is approved.
NNECO (Harris) stated that the entire analysis would be conservative for operation at 2560 MWt.
Enclosures 3 and 10 were passed out and discussed. The staff (Kapo) questioned the Fr and Fq values of 6% and 7% as given in Enclosure 8.
A graph (claimed to be proprietary by NNECO) showing the peak clad temperature expected during the small break LOCA evaluation was discussed.
This graph showed that an acceptable peak clad temperature of 1945 F could result only if credit is taken for 20 gpm flow frca the charging pumps. NNECO pointed out that this system is fully qualified and similar systems have been authorized for credit in small break LOCA analysis at other facilities. NNECO (Kacich) agreed to make appli-cation for using the 20 gpm flow from the charging pumps in this manner in a few weeks, ahead of the remainder of the reload submittal.
The concluding item discussed was the submittal schedule given out (Enclosure 11) by NNECO (Kacich). The staff (Conner) pointed cut that this schedule would likely not allow the staff to complete its review for stretch power on the schedule requested. The staff's schedule (Enclosure 3) contains the minimum time intervals.
NNECO (Kacich) indicated that further discussions would be held with CE to resolve these scheduling differences.
f m W $~/
A J
E. L.' Conner, Project Manager Operating Reactors Branch #4 Division of Operating Reactors
Enclosures:
1.
List of Attendees 2.
Agenda for Meeting 3.
HRC Tentative Review Schedule 4.
CEA Guide Tube Wear Basis 5.
Cycle 2 & 3 Assemblies Under CEA's 6.
RCPSS S 7.
Diagram 8.
Table I - Low Flow Trip Function Nominal Characteristics 9.
Key Changes from Cycle 2
- 10. ECCS Evaluation
- 11. Schedule of Submittals
MILLSTONE 2 STRETCH POWER MEETING 11/21/78 Name Oroanization Monte Conner NRC, ORB #4, 00R John F. Burdoin NRC, PSB, 00R George W. Knighton NRC, EEB, D0R Donald S. Brinkman NRC, STSG, DOR Audrey Smith NRC, EEB, DOR E. G. Adensam NRC, EEB, 00R Richard E. Johnson NRC, EEB, D0R X. I. Parczewski NRC, RSB, 00R Thomas D. Cain NRC, ESS, 00R Peter S. Kapo NRC, RSB, 00R R. W. Reid NRC, ORB #4, 00R E. V. Imbro NRR, RSB, D0R S. H. Weiss NRR, RSB, 00R Arnold R. Roby NUSCO Richard D. Hart NUSCO Richard M. Kacich NUSCO Robert T. Harris NUSCO
AGENDA FOR MILLSTONE 2 STRETCH POWER MEETING NOVEMBER 21, 1978 1.
NRC Opening Remarks 2.
NNEC0 General Discussion 3.
Environmental Impact Review (ESB) 4.
Radiological Impact Review (EEB) 5.
CEA Guide Tube Wear Review (EB) 6.
RCP Speed Sensing System Review (PSB)
T and F Uncertainties, 7.
Core Physics and Thermal Hydraulics, F Analyses Codes, A00 and LOCA Evaluation (RS) 8.
Miscellaneous
NRC TENTATIVE MILLSTONE 2 STRETCH POWER REVIEW SCHEDULE COMPLETION DATE ITEM NNECO STAFF Submittal on RCP Speed Sensing System 11/ 8/78 Submittal of Neutron Shield Design ll/13/7C Request for Reload / Stretch Power Including Radiological /
Environmental Considerations 1/2/79 Submittal of CEA Guide Tube Wear Evaluation Program 1/10/79 Information Letter to ACRS 1/15/79 Pre-Notice to Federal Register 2/1/79 Submittal of Large & Small Break LOCA 2/5/79 Request for Additional Information 2/23/79 All Responses from Licensee 3/16/79 Technical Input Completed 3/26/79 Technical Specifications Completed 4/2/79 SE to ACRS 4/9/79 ACRS Subcommittee 4/23/79 4/23/79 EIA Completed 5/1/79 ACRS Review 5/3/79 5/3/79 Issuance of Amendment 5/15/79
CEA GUIDE TUBE WEAR: CYCLE 3 BASIS FOR REDUCED FLOW G.T.'s & SLEEVIf1G REDUCED FLOW ELIMINATES CAUSE COMBINATION OF REDUCED FLOW G.T.'s PLUS SLEEVE IS PRUDEllT TRAtlSITIONAL STEP FOUR REDUCED FLOW ASSEMBLIES UtlDER SIllGLE CEA's WILL PROVIDE SCRAM TIMES AND DEM0f1 STRATE PERFORMANCE 245 HOUR WEAR TEST SHOWED NEGLIGIBLE WEAR FURTHER EVALUATION OF IMPACT ON I?iCORE IflSTRUMENTATIOil IS fiEEDED ASSURES COMPATABILITY U!iDER DUAL CEA's
CYCLE 2 BATCil B BATCil C BATCil D TOTAL SLEEVED ASSEMBLIES 45 16 12 73 UtIDER CEA's ADDIT!0tlAL SLEEVED 16 J6 ASSEMBLIES 89 CYCLE 3 - ASSEMBLIES UtlDER CEA's BATCil B BATCil C BATCil D BATCil E (fresh)
TOTAL PRESEllTLY SLEEVE'.
4 8
12 SLEEVillG REQUIRED 5
12 28 12 57 REDUCED FLOW GUIDE 4
_4 73 TUBE ASSEMBLY T
S 40 BATCil E REDUCED FLOW ASSEMBLIES fl0T UtIDER CEA's WILL BE USED DtlRiflG CYCLE 3 28 BATCll E ASSEMBLIES Ill DUAL CEA ATID lilSTRUMEllT LOCATI0flS WILL BE SLEEVED FOR CYCLE 3
FIGURE 1 REACTOR C00LAtlT PUMP SHAFT SPEED SEriSirlG SYSTEM
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TABLE I LOW FLOW TRIP FUNCTI0tl NOMINAL CHARACTERISTICS PERFORMANCE CHARACTERISTICS LOW FLOW TRIP FUNCTION RCPSS TRIP FUNCTION (STEAM GENERATOR AP)
System Overall Accuracy 2.7%
1.5%
Bistable Drift Allowance 0.8%
0.8%
System floise 2.25%
1.0%
Nominal Trip Setpoint 91.7%
93%
Overall System Response Time 650 msec 450 msec E'2 8
5 m
CD e
KEY CHAilGES FROM CYCLE 2 MODEL CHAtlGES:
1.
T-H MODEL - TORC /CEl (CYCLE 2 - COStiO/W3) 2.
SitALL BREAK MODEL - tiODELIflG CHAtlGES TO CEFLASH - 4AS 3.
USE OF ROCS FOR SCOPIflG CALCULATI0riS Afl0 SELECTED CEA WORTHS 4.
EVALUATING USE OF STATISTICALLY COMBIrlIrlG UNCERTAltlTIES:
SETPOIllTS
- THERftAL ttARGIfl IflPUT CHANGES 1.
CORE PCadR 2700 MWt (CYCLE 2 - 2560 ftWt) 0 2.
T inlet 549 F (CYCLE 2 - 5420F) 3.
SCRAM TIME 3.1 SEC (CYCLE 2 - 2.75 SEC) 4.
UNCERTAINTIES 6% Oil Fr (AS AGREED TO BET.1EEN 7% Oil Fq NRC AND CE) 5.
SMALL BREAK LOCA:
CREDIT FOR 20 GPM CHARGING FLOW
.. 0 ECCS EVALUATION CYCLE 2 0
SMALL BREAK PCT = 1931 0
LARGE BREAK 0.8 DES /PD PCT = 2160 F C 5.6 KW/FT CYCLE 3 0
SMALL BREAK (FULL SPECTRUM)
PCT R1945 F (CELEVEL)
LARGE BREAK (FULL SPECTRUM)
EXPECT RESULTS COMPARABLE TO CYCLE 2
J 1 MILLSTONE (filT NO. 2 POWER UPRATING SCHEDULE OF SUBMITTALS CRITICALITY SCHEDULED MAY 15, 1979 (1) RCP SPEED SENSING SYSTEM NOVEMBER 8, 1978 (2) NEUTRON SHIELDING NOVEMBER 13, 1978 (3) ENVIRONMENTAL, RADIOLOGICAL 9ECEMBER 15, 1978 (4) NON-LOCA SAFETY ANALYSIS, TECHNICAL SPECIFICATION CHANGES FEBRUARY 1,1979 (5) FORMAL LARGE BREAK LOCA RESULTS MARCH 15, 1979 (6) FORMAL SMALL BREAK LOCA RESULTS APRIL 25, 1979 e