ML17174B012
| ML17174B012 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, Zion, LaSalle  |
| Issue date: | 11/13/1991 |
| From: | Barrett R Office of Nuclear Reactor Regulation |
| To: | Kovach T COMMONWEALTH EDISON CO. |
| References | |
| IEB-88-008, IEB-88-8, TAC-M69625, TAC-M69626, TAC-M69644, TAC-M69645, TAC-M69675, TAC-M69676, TAC-M69710, TAC-M69711, NUDOCS 9112060363 | |
| Download: ML17174B012 (10) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 November 13, 1991 Docket Nos.
and J
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50-237, 50-249~ 50-254, 50-265 50-2,5, 50-\\04, 50-~73, 50-\\74 Mr. Thomas J. Kovach Nuclear Licensing Manager Conunonwealth Edison Company-Suite 300 OPUS West III 1400 OPUS Place Downers Grove, Illinois 60515 Dear Mr.
SUBJECT:
Kovach:
NRC BULLETIN NO. 88-08, "THERMAL STRE,SES IN~ING ~NNEC D TO REACTOR COOLANT SYSTEMS" (TAC NOS. 69625, 69626, 69~~' 69645, 69675, 69676, 69710 AND 69711)
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By letters dated October 3, 1988 and July 17, 1989, Conunonwealth Edison Company responded to NRC Bulletin No. 88-08 (Bulletin). Your response stated that the required reviews were performed of piping connected to the reactor coolant system (RCS).
The NRC staff and its consultant, Brookhaven National Laboratories, have completed the review of your response to the Bulletin and its supplements.
The staff has determined that your response for Dresden, Units 2 and 3, Quad Cities, Units 1 and 2, Zion, Units 1 and 2, and LaSalle, Units 1 and 2, is consistent with modification or monitoring alternatives stated in the Bulletin._
Your response to the Bulletin for the Byron and Braidwood Stations is not consistent with recommended actions and is the subject of additional correspondence.
Although no response was required related to Supplement 3 of the Bulletin, some licensees have addressed it. Those who have not, will not be required to provide a specific response to Supplement 3.
Ho~; ~r, you are reminded that having been informed of the phenomenon identified in that supplement, you are responsible for adequate review of both its applicability to your plant and any considered actions. The NRC staff may audit or inspect the implementation of NRC Bulletin No. 88-08 and its supplements at a later date. The enclosure contains information that you may use to assess the adequacy of your program with respect to Action 3 of the Bulletin, and Supplement 3.
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- Mr. Thomas November 13, 1991 Therefore, you meet the requirements of NRC Bulletin No. 88-08 and no further action is required. This completes our activity on TAC Nos. 69625, 69626, 69644, 69645, 69675, 69676, 69710 and 69711.
Enclosure:
Evaluation Criteria cc w/enclosure:
See next page DISTRIBUTION Doe:ket... u:t-~
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BClayton, Rill LOlshan CPatel BMozaf ari NRC & Local PDRs BBoger RBarrett CMoore EJordan, MNBB 3701 PDIII-2 Gray File BSiegel JHickman RElliott Sincerely, Original Signed By:
Richard J. Barrett, Director Project Directorate III-2 Division of Reactor Projects - Ill/IV/V Office of Nuclear Reactor Regulation
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- DOCUMENT NAME: KOVACH 69625/6/44/5/75/6 ET Al
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Mr. Thomas-J. Kovach Conmonwealth Edison Company cc:
Michael I. Miller, Esq.
Sidley and Austin One First National Plaza Chicago, Illinois 60690 Mr. J. Eenigenburg Plant Superintendent Dresden Nuclear Power Station Rural Route fl1
~orris, Illinois 60450 U. S.. Nuclear Regulatory Conmission Resident Inspectors Office Dresden Station Rural Route #1 Morris, Illinois 60450 Chairman Board of Supervisors of Grundy County Grundy County Courthouse Morris, Illinois 60450 ReQional Administrator Nuclear Regulatory Commission, Region III 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois 60601
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Dresden Nuclear Power Station Unit Nos. 2 and 3
Mr. Thomas J. Kovach Col'l1Tlonwealth Edison Company cc:
Mr. Stephen E. Shelton Vice President Iowa-Illinois Gas and Electric Company P. 0. Box 4350 Davenport, Iowa 52808 Michael I. Miller, Esq *.
Sidley and Austin One First National Plaza Chicago, Illinois 60690 Mr. Richard Bax Station Manager Quad Cities Nuclear Power Station 22710 206th Avenue North Cordova, Illinois 61242 Resident Inspector U. S. Nuclear Regulatory Commission 22712 206th Avenue North Cordova, Illinois 61242 Chairman Rock Island County*Board of Supervisors 1504 3rd Avenue Rock Island County Office Bldg.
Rock Island, Illinois 61201 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Regional Administrator, Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois 60601 Quad Cities Nuclear Power Station Unit Nos. 1 and 2
Mr. Thomas J. Kovach Commonwealth Edison Company cc:
Michael I. Miller, Esq.
Sidley and Austin One First National Plaza Chicago, Illinois 60690
. Dr. Cecil Lue~Hing Director of Research and Development Metropolitan Sanitary District of Greater Chicago 100 East Erie Street Chicago, Illinois 60611 Phillip Steptoe, Esq.
Sidley and Austin One First National Plaza Chicago, Illinois 60603 Mayor of Zion Zion, Illinois 60099 I 11 i noi s Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 U.S. Nuclear Regulatory Commission Resident Inspectors Office 105 Shiloh Blvd.
Zion, Illinois 60099 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois 60601 Zion Nuclear Power Station Unit Nos. 1 and 2
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Mr. Thomas J. Kovach Commonwealth Edison Company cc:
Phillip P. Steptoe, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 60603 Assistant Attorney General 100 West Randolph Street Suite 12 Chicago, Illinois 60601 Resident Inspector/LaSalle, NPS
- U.S. Nuclear Regulatory Commission Rural Route No. 1 P. 0. Box 224 Marseilles, Illinois 61341 Chairman LaSalle County Board of Supervisors LaSalle County Courthouse Ottawa, Illinois 61350 Attorney General 500 South 2nd Street Springfield, Illinois 62701 Chairman Illinois Commerce Commission Leland Building 527 East Capitol Avenue Springfield, Illinois 62706 Illinois Department of Nuclear Safety Office of Nuclear Facility.Safety 1035 Outer Park Drive Springfield, Illinois 62704 Regional Administrator, Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois 60601 LaSalle County Station Unit Nos. 1 and 2 Robert Cushing Chief, Public Utilities Division Illinois Attorney General's Office 100 West Randolph Street Chicago, Illinois 60601 Michael I. Miller, Esq.
Sidley and Austin One First National Plaza Chicago, Illinois 60690
Enclosure EVALUATION CRITERIA FOR RESPONSES TO NRC BULLETIN 88-08, ACTION 2 AND SUPPLEMENT 3 1.0 OBJECTIVE To provide continuing assurance for the life of the plant that unisolable sections of piping connected to the reactor coolant system {RCS) will not be subjected to thermal stratification and thermal cycling that could cause fatigue failure of the piping.
2.0 PURPOSE To provide guidelines for evaluation of licensee responses, including acceptable procedures and criteria to prevent crack initiation in susceptible unisolable piping.
3.0 IDENTIFICATION OF POTENTIALLY SUSCEPTIBLE PIPING (1) Sections of injection piping systems, regardless of pipe size, which are normally stagnant and have tht fol lo~dng characteri sties:
A.
The pressure is higher than the RCS pressure during reactor powe~ operation.
B.
The piping sections tontain long horizontal runs.
C.
The piping systems are isolated by one or more check valves and
. a closed isolation valve in series.
D.
For sections connected to the RCS:
- a.
Water injection is top or side entry.
- b.
The first upstream check valve is located less than 25 pipe diameters from the RCS nozzle.
ExamplE:s of such sections in PWRs are the safety injection lines and charging lines *between the reactor coolant loop and the first upstream check valve, and the auxi 1 iary pressurizer spray 1 ine between the charging line and the main pressurizer spray line.
(2)
S~ctions of other piping systems connected to the RCS, regardless of pipe size, which are normally stagnant and have the following characteriltics:
A.
The downstream pressure is lower than RCS pressure during reactor power operation.
B.
The piping systems are isolated by a closed isolation valve, or a check valve in series with a closed isolation valve.
C.
There is a potential for external leakage from the isolation valve.
- Examples of p1p1ng containing such uniso1able sections in PWRs are the residua1 heat removal (RHR) lines. Examples of such piping for BWRs are the RHR 1 ine:s arid tht core spray injection lines.
4.0 ACCEPTABLE ACTIONS The fullowing actions are considered as acceptable responses to Bu11etin 88-08. Action 3 and Supplement 3. as applicable. provided that the requirements of Bulletin 88-08. Action 2 have been satisfied.
(1) Revision of system operating conditions to reduce the pressure of the water upstream of the isolation valve below the RCS pressure during power operation.
(2) Relocation of the check valves closest to the RCS to be at a distance greater than 25 pipe diameters from the nozzle.
(3) Installation.of temperature monitoring instrumentation for det£ction of piping thermal cycling due to valve leakage.
A.
Type and location of sensors.
- b.
- c.
- d.
- e.
Ttmp~rature sensors should prEferably be resistance t~mperature detectors (RTDs).
RTDs should be located between the first elbow (elbow closest to the RCS). and the first check va1ve (check va1ve closest to the RCS}.
For the auxi1iary pressurizer spray line. RTDs shou1d be installed near the "tee" connection to the main pressurizer spray 1ine or on the co1d portion (ambient temperature) of the line.
RTDs should be located within six inches of the welds.
At each pipe cross section, one RTD shou1d be positioned on the top of the pipe and another RTD on the bottom of the pipe.
B.
Determination of baseline temperature histories.
Aft~r RTD installation, temperature should be recorded during normal plant operation at every location over a period of 24
- hours.
The resulting temperature versu~ time records represent the baseline temperature histories at these locations. Bastline temperature histories should meet the following criteria:
- a.
The maximum top-to-bottom temperature difference should not exceed 50°F.
- b.
Top and bottom temperature time histories should be in-phase.
- c.
Peak-to-peak temperature fluctuations should not exceed 60°F.
C.
Monitoring time intervals.
- a.
Monitoring should be performed at the following times:
- 1.
At. the beginning of power operation, after startup.
from a refueling shutdown
- 2.
At least at six-month intervals thereafter, between refueling outages
- b.
During each monitoring period, temperature readings should be recorded continuously for a 24-hour period.
D.
Exceedance Criteria.
- Actions should be taken to modify piping secti~ns or to correct valv~ leakage if the following conditions occur:
- a.
The maximum temperature difference between the top and the bottom of the pipe exceeds 50°F.
- b.
Top and bottom temperature histories are in-phase but the peak-to-peak fluctuations of the top or bottom temperatures exceed 60°F.
- c.
Top and bottom temperature histories are out-of-phase and the bottom peak-to-peak temperature fluctuations exceed 50°F.
- d.
Temperature histories do not correspond to the initially recorded baseline histories.
'* (4)
Installation of pressure monitoring instrumentation for leakage detection in injection lines.
(Pressure monitoring is not the pref erred method since pressure measurements cannot provide a measurement of thermal cycling in the unisolable pipe sections.)
A.
Type and location of sensors.
- a.
Pressure sensors should preferably be pressure transducers.
- b.
Pressur~ transducers should be installed upstream and downstream of the first check valve.
- c.
For systems having a pressure higher than the RCS pressure, pressure transducers may be installed upstream and down-stream of the first closed isolation valve.
(The downstream section is the pipe segment between the isolation valve and the check valve.)
B.
Monitoring time intervals.
- a.
MonHoring should be performed at the following times:
- 1.
At the beginning of power operation, after startup from a refueling shutdown
- 2.
At least at six-month intervals thereafter, bet\\-1een refueling outages
- b.
Pressure readings should be recorded continuously for a 24-hour period.
C.
Exceedance criteria.
Actions should be taken to modify piping sections or to corrtct va1v, leakage if the following conditions occur:
- a.
For pressure measurements across a check valve, the downstream pressure (RCS pressure) is equal to or less than the upstream pressure at any time during power operation.
- b.
For pressure measurements across a closed isolation valve, the downstream pressure is equal to or greater than the upstream pressure at any time during power operation.