ML20070L303

Forwards Response to NRC 820922 Request for Addl Info Re Secondary Water Chemistry Monitoring & Control Program

ML20070L303
Person / Time
Site:	Davis Besse
Issue date:	12/22/1982
From:	Crouse R TOLEDO EDISON CO.
To:	Stolz J Office of Nuclear Reactor Regulation
References
874, NUDOCS 8301030078
Download: ML20070L303 (12)

Text

,

TOLEDO

%s EDISON Docket No. 50-346 u.-

YCm License No. NPF-3 " 'S'858-58 '

Serial No. 874 December 22, 1982 Director of Nuclear Reactor Regulation Attention: Mr. John F. Stolz Operating Reactor Branch No. 4 Division of Operating Reactors United States Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Stolz:

This is in response to your letter dated September 22, 1982 (Log No. 1089) concerning Secondary Water Chemistry Monitoring and Control. The attachment contains Toledo Edison's response to your letter for Davis-Besse Nuclear Power Station Unit No. 1.

Very truly yours, l  ;+^- --

RPC: GAB:lah attachment cc: DB-1 NRC Resident Inspector THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO. OHIO 43652 O 8301030078 821222 b PDR ADOCK 05000346 P PDR

4 Docket No. 50-346 License No. NPF-3 Serial No. 874 December 22, 1982 Attachment

, SECONDARY WATER CHEMISTRY MONITORING PROGRAM

_ DAVIS-BESSE NUCLEAR POWER STATION UNIT NO. 1 I. Provide a summary of operative procedures to be used for the steam generator secondary water chemistry control and monitoring program, addcessing the following:

Note: Toledo Edison received a license amendment dated October 15, 1982 concerning Secondary Water Chemistry. With the amendment was a License Condition which requires Toledo Edison to implement and maintain a program for secondary water chemistry. See below.

Add paragraph 2.C.(5) to read as follows:

Toledo Edison Company shall maintain in effect and implement a secondary water chemistry monitoring program to inhibit steam generator tube degradation. The program shall include:

(a) Identification of a sampling schedule for the critical parameters and control points for these parameters; (b) Identification of the procedures used to quantify parameters that are critical to control points; (c) Identification of process sampling points; (d) Procedure for the recording and management of data;

, (c) Procedures defining corrective actions for off control point chemistry conditions; and I (f) A procedure identifying the authority responsible for the interpretation of the data, and the sequence and timing of administrative events required to initiate corrective action,

1. Sampling frequency for the critical chemical and other parameters and of control points or limits for these parameters for each mode of operation: normal operation, hot startup, cold startup, hot shutdown, cold wet layup;

Response: SECONDARY WATER CONTROL POINTS AND SASPLING FREQUENCIES A. General Proper feedwater conditioning, or quality, is required to maintain the operational capability of the steam generator. Good water quality minimizes fouling of the steam generator heating surfaces and.

subsequent loss of efficiency of the steam generator. The net result is that the frequency of " soaking" and " flushing" or chemically cleaning the steam generator is reduced.

B. Feedwater Quality for Normal Power Operations The most representative sample point of final feedwater and the one at which all specifications must be met is the No. 6 Feedwater Heaters' Common Outlet Header. Samples of feedwater should be-analyzed and must conform to NSSS minimum standards.

Minimum Specification Frequency Cation Conductivity, pmho/cm, max. 0.5 Daily Dissolved Oxygen, ppb, max. 7 Daily Total Silica (as SiO 2), PP b, max. 20 Daily Total Iron (as Fe), ppb, max. 10 Daily Total Copper (as Cu), ppb 2 Monthly pH at 77F (adjusted with ammonia) 9.2-9.6 Daily

! Lead 0 Monthly f Hydrazine, ppb, min. 20 Daily l

l Maintaining the steam generator feedwater within the limits will control the introduction of potentially corrosive impurities into the steam generators and minimize tube degradation. This monitoring provides reasonable assurance that the chemistry conditions in the steam generators minimize the potential for tube degradation during all' conditions of operation and postulated accidents, as a measure of-protection of the steam generator tubing which provides part of the reactor coolant pressure boundary.

C. Condensate System The limitations on secondary feedwater cation conductivity minimized the degradation of the steam generator tubes and the potential for steam ' generator tube leakage or failure due to stress corrosion.

Contamination of the steam generator secondary coolant increases the potential of tube degradation and the impairment of tube integrity.

The condenser circulating water chemistry is a relatively consistent, low solids water, approximately two cycles of concentration over Lake Erie water. The main surface condenser contains tubes of Type 304 stainless steel and has a deaerating section. This fact, combined with full-flow condensate polishing, virtually nullifies any attempt to relate the chemistry of the circulating water, the demineralized makeup water, and the condensate to the steam generator feedwater quality under normal conditions. However, continuous, in-line equipment is installed at the condensate pump discharge to monitor cation conductivity, oxygen, and sodium to make possible an early detection of condenser leakage. More important to good feedwater

-chemistry is the operation of the condensate polishing system.

Generally, the most severe contamination results from condenser inleakage of impurities that may enter the secondary side of the steam generators if breakthrough of the condensate polishing demineralizers occurs. This is a powdered resin type system. Being a powdered resin system, the potential for-regeneration chemical contamination of the feedwater is eliminated. There are no resin strainers downstream of this system but the minimal quantity of resin leakage existing presents no detectable adverse effects and would not be stopped by conventional strainers anyway. Continuous monitoring of the secondary feedwater by cation conductivity is an effective means of monitoring condensate polishing demineralizer breakthrough and minimizing the introduction of contaminants to the steam generator.

D. Moisture _ Separator Reheater Drains Another source'of feedwater contamination is the moisture separator drains. In the original plant design, these drains are pumped forward to become feedwater at the deaerating heaters, thus bypassing the condensate polishers. In order to maintain very high steam generator feedwater quality, one-half of the moisture separator drain flow is routed to the condenser at all times for cleanup through the condensate polishers.

E. General Philosophy of Operation The most harmful contaminants found in the secondary side are suffi-ciently soluble in the very low concentrations in the final feedwater that they carry over in the superheated steam, and, for the most part, do not accumulate or concentrate _in the steam generators. For the very small amount of chemical contaminant " hideout" on the steam generator surfaces, we practice a procedure to remove these contami-tants on each shutdown. The station procedure which contains generally all the operational chemical specifications, sample points, and sample frequencies is PP1101.04, Operational Chemical Control Limits.

_4 OTSG Water Chemistry Specifications During Extended Operation at <15% Full Power Analyses Specifiation Frequency of Required Sample Point Range Analysis, Hrs.

c Chloride, Lower tube- 1.0 max Every 8 ppm sheet drain line Sodium, Lower tube- 2.0. max Every 8 ppm sheet drain line pH at Lower tube- Set By Every 8 77F sheet drain Feedwater line pH Cation Lower Tube- 10.0 max Every 8 conducti- sheet drain vity, line pmho/cm Silica OTSG drain 2.0 max Every 8 line

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OTSG Water Chemistry Specifications During Layup Analyses Specifiation Frequency of Required Sample Point Range Analysis, Hrs.

Ammonia, OTSG recircu- 5-20 Initially, ppm lation line daily until chemistry has stabilized; thereafter, weekly Hydrazine, OTSG recircu- 50-200 ppm lation line pH at 77F OTSG recircu- 9.5-10.5 lation line Cation OTSG recircu- 10.0 max conducti- lation line vity, pmho/cm Sodium, OTSG recircu- 1.0 max.

ppm lation line I

Chloride, OTSG recircu- 1.0 max.

4 ppm lation line e

. , - , , n -- ,- -

2. Procedures used to measure the values of the critical parameters; Response:. PROCEDURES FOR QUANTIFYING CRITICAL CONTROL POINT PARAMETERS The following Toledo' Edison chemistry procedures are used to quantify the critical control point parameters for the steam generator feedwatec:

CH 4078.00 pH Determination CH 4079.00 Silica CH 4023.00- Dissolved Oxygen (Indigo Carmine Method)

CH 4060.00 Cation Conductivity'

. CH 4061.00 Conductivity CH 4072.00 Iron, Membrane Filter CH 4071.00 Total Iron CH 4062.00 Copper CH 4091.00 Chloride CH 4097.00 Hydrazine CH 4000.00 Atomic Absorption

3. Location of process sampling points; Response: IDENTIFICATION OF PROCESS SAMPLING POINTS The sample point for the steam generator feedwater is at a point downstream of the highest pressure feedwater heater. At the sampling station for this point are the following continuous analyzer / recorders:

sodium, hydrazine, raw conductivity, and cation conductivity. These monitors are used in addition to the grab samples to maintain a tight control on final feedwater chemistry. In addition to the final feedwater sample point, the following sample points are used to monitor and maintain strict feedwater chemistry controls throughout the cycle: l Sample Point Monitoring Capabilities Condensate Pump Common Continuous sodium, oxygen, and cation Discharge conductivity analyzers / recorders Condensate Polisher Outlet Contintous sodium analyzer and cation conductivity analyzer / recorder Deaerator Storage Tank Continuous oxygen analyzer / recorder Outlet and continuous pH monitor / recorder

'l Steam Generator Water Continuous raw and cation conductivity _

monitors / recorders Steam Generator. Steam Continuous sodium analyzer / recorder and raw and cation conductivity monitors / recorders Moisture Separator Drains- Continuous sodium analyzer / recorder and raw and cation conductivity monitors / recorders

4. Procedure for the recording and management of data; Response: PROCEDURES FOR THE RECORDING AND MANAGEMENT OF DATA Management and recording of data for the chemistry section at Davis-Besse Nuclear Power Station Unit 1 is controlled by the following Toledo Edison Procedures.

AD 1842.00 Chemistry and Health Physics AD 1848.10 Control and disposition of records generated by the DBNPS Chemistry and Health Physics Section

5. Procedures defining corrective actions for off-control point chemistry conditions detailing time allowed at off-chemistry conditions; and Response: PROCEDURES FOR CORRECTIVE ACTION FOR OFF CONTROL POINT CONDITIONS Cation conductivity is a measurement that is used to monitor the general feedwater quality. It also determines the action levels in correcting feedwater chemistry upset conditions. The cation con-ductivity specification for normal operation is 0.5 paho/cm maximum, but the following criteria shall be used for operating the plant during abnormal feedwater conditions:

Allowable time to correct Cation conductivity high feedwater conductivity range, pmho/cm before shutdown is required, hrs.

Above Below 0.5 1.0 24 1.0 2.0 12 2.0 --- 0 I (initiate normal procedure for plant cooldown)

l ,

t -The following Toledo Edison procedures define the corrective actions I required for off control point conditions.

EP 1202.23 Steam Generator Feedwater Out of Specification EP 1202.57 Steam Generator Tube Leak l- AB 1203.10 Condenser Tube Leak AP 3034.01 Condensate Pump Discharge or Second Stage Feedwater Heater Outlet Sodium Hi AP 3034.02 Condensate Pump Discharge or Second Stage Feedwater j Heater Outlet Cation Conductivity Hi i

AP 3034.03 Condensate Polishing Demineralizer Inlet Cation Conductivity Hi AP 3034.04 Condensate Polishing Demineralizer Outlet Cation Conductivity Hi 1 AP 3034.05 Condensate Pump Discharge Oxygen Concentration Hi AP 3034.06 Deaerator St,orage Tank Outlet Oxygen Concentration Hi j AP 3034.07 Deaerator Storage Tank Outlet pH Hi or Lo i

AP 3034.08 Feedwater Heater 1-1-6 or 1-2-6 Outlet Cation Conductivity Hi AP 3034.09 Feedwater Heater 1-1-6 and 1-2-6 Outlets Hydrazine Hi ,

< or Lo

AP 3034.10 Steam Generator 1-1 Water Cation Conductivity Hi AP 3034.11 Steam Generator 1-2 Water Cation Conductivity Hi AP 3034.12 Steam Generator 1-1 Steam Sodium Hi AP 3034.13 Steam Generator 1-1 Steam Cation Conductivity Hi AP 3034.14 Steam Generator 1-2 Steam Sodium Hi i

AP 3034.15 Steam Generator 1-2 Steam Cation Conductivity Hi AP 3041.01 Condensate Demineralizer 1-1 Differential Pressure Hi AP 3041.02 Condendate Demineralizer 1-2 Differential Pressure Hi 4 AP 3041.03 Condensate Demineralizer 1-3 Differential Pressure Hi AP 30*41.04 Condensate Demineralizer 1-4 Differential Pressure Hi

+ AP 3041.05 Air Failure (Condensate Demineralizer) 4

. _ , _ . . . - . - - . _ _ _ _ - , - . . . _ . _ _ _ _ . . . - , , . - , _ _ . . . . . _ _ . , , , . , . ...e__7 ,_.m_-

AP_3041.06 Condensate Demineralizer 1-1 Outlet Conductivity Hi AP 3041.07 Condensate Demineralizer 1-2 Outlet Conductivity Hi AP 3041.08 Condensate Demineralizer 1-3 Outlet Conductivity Hi AP 3041.09 Condensate Demineralizer 1-4 Outlet Conductivity Hi AP 3041.10 Power Failure (Condensate Demineralizer)

AP 3041.11 Condensate Dem.ineralizer 1-1 Flow High/ Low AP 3041.12 Condensate Demineralizer 1-2 Flow High/ Low AP 3041.13 Condensate Demineralizer 1-3 Flow High/ Low AP 3041.14- Condensate Demineralizer 1-4 Flow High/ Low AP 3041.15 Low Level Precoat Tank

6. The procedures identifying (a) the authority responsible for the interpretation of the data and (b) the sequence and timing of adminis-trative events required to initiate corrective action.

Response: ADMINISTRATIVE CONTROLS The attached organizational chart shows the division of responsibility within the Chemistry and Health Physics Section at Davis-Besse Nuclear Power Station Unit No. 1. The following procedures detail the administrative actions required for initiation of corrective action for off-control point chemistry conditions.

AD 1842.00 Chemistry and Health Physics Also, see procedures lised in Pert 5 above.

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CHEMIST & HEALTH PHYSICIST l

HEALTH PHYSICS SUPERVISOR SUPERVISOR CHEMISTRY & HEALTH CHEMISTRY & HEAI.TH PHYSICS FOREMAN

{PHYSICSFOREMAN l

GROUP LEADERS SR. CHEM & RAD TESTERS

. CHEM & RAD TESTERS ASST CHEM & RAD TESTERS j

1 DAVIS ,BESSE NUCLEAR POWER STATION, UNIT No. 1 CHEMISTRY & HEALTH PHYSICS ORGANIZATION CHART l

November 8, 1982

II. Verify that the steam generator secondary water chemistry control program incorporates technical recommendations of the NSSS. Any

-significant deviations from NSSS reconnendations should be noted and justified technically.

Response: The specifications are virtually identical to those recommended by Babcock & Wilcox the NSSS vendor.

III. In addition to the secondary water chemistry monitoring and control program, we require monitoring of the steam condensate at the effluent of the condensate pump. The monitoring of the condensate is for the purpose of detecting condenser Icakage. Verify that the steam condensate at the effluent of the condensate pump is monitored.

Response: A continuous, in-line equipment is installed at the condensate pump discharge to monitor cation conductivity, oxygen, and sodium to make an early detection of condenser leakage. A grab sample of this same point is also analyzed daily.

IV. If demineralizers are used, explain how you prevent resin breakthrough into the steam generator.

Response: There are no resin strainers downstream of this system but the minimal quantity of resin leakage existing presents no detectable adverse effects and would not be stopped by conventional strainers anyway. Continuous monitoring of the secondary feedwater by cation conductivity is an effective means of monitoring condensate polishing demineralizer breakthrough and minimizing the introduction of contaminants to the steam generator.

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