ML20247D852

Forwards Response to NRR 890427 Request for Addl Info Re Plant Accident Monitoring Program

ML20247D852
Person / Time
Site:	Comanche Peak
Issue date:	05/19/1989
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TXX-89253, NUDOCS 8905260020
Download: ML20247D852 (7)

Text

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5 Log # TXX-89253

. .-" File # 907.5

. 7UELECTR/C May 19. 1989 l

Wullam J. Cahul, Jr.

t Executive Vice President I.

U. S. Nuclear. Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 NRR REQUEST FOR ADDITIONAL INFORMATION REGARDING THE CPSES ACCIDENT MONITORING PROGRAM'

. Gentlemen:

On April 27, 1989, NRR verbally contacted TV Electric and requested additional information regarding the implementation of Regulatory Guide 1.97 Revision 2 requirements for the CPSES Accident Monitoring' Program. Attached are the NRR questions and the TV Electric responses.

Sincerely, William J. Cahill, Jr.

VPC/ddm ,

Attachments- '

c - Mr R. D. Martin, Region IV Resident Inspectors, (CPSES) (3)

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8905260020 890519 1 PDR ADOCK 05000445 l' A PDC .g l 400 North Olive Street LB81 Dallas, Texas 73201 Q- _ _ _ _ _ _ _ _ _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ . - _ _ _ _ _ _ _ _ _ _ _ . - _ _ . _ _ _ _ _ _ _ - - - - _ _ _ _ _ _ _

Attachment to TXX-89253 May 19, 1989 Page 1 of 6 NRC Ouestion (1)

RADIATION EXPOSURE RATE: The rarges for the identified instrumentation does not include the ranges recommended by Regulatory Guide 1.97. For example, control room area, post accident sampling system room area, plant vent stack area, and hot lab area instruments have ranges of 10E-1 to 10E4 mR/hr, XRE-6273 and XRE-6275 have ranges of 10E-1 to 10E4 mR/hr, and RE-5637 has a range of 10E-10 to 10E-5 Ci/cc, whereas the recommended range is 10E-1 to 10E4 R/hr. The applicant should show that the provided ranges encompass all expected radiation levels at their locations in support of these deviations.

The applicant should describe why this is considered a Category 3 backup variable.

TV Electric Response (1)

CPSES takes credit for the 10E-1 mr/hr to 10E4 mr/hr versus 10E-1 R/hr to 10E4 R/hr because of the anticipated access requirements to the areas monitored in the plant during an accident. The control room area, hot lab area, accident sampling area and plant vent stack area by design are required to be habitable during all postulated accidents. A low end range of 10E-1 R/hr or 100 mr/hr would be too high to provide useful protection to personnel entering these areas following an accident. FSAR section II.B.2 describes the specific dose rates and durations of operator activities during an accident.

Area monitors X-RE-6273 and X-RE-6275 are located in the fuel building.

During fuel transfer, it is desirable to have indication that monitors any noticeable increase in dose rates. Therefore, the CPSES design utilizes a lower range monitor. Futhermore, the fuel building would become uninhabitable long before the top end of the scale,10E4 mr/hr, would be reached during an accident.

The in-line gaseous monitor, 1-RE-5637, provides indication of airborne activity in the main steam and feedwater pei,etration area ventilation exhausts. Because this is an in-line monitor rather than an area monitor, it is appropriate to measure radioactive concentrations rather than dose rates.

For normal and accident conditions, personnel entries into potentially contaminated areas are approved by Radiation Protection Personnel. Portable monitors are utilized by Radiation Protection to assess the radiation environment of areas requiring personnel entry. The CPSES design considers portable instrumentation more reliable than fixed area monitoring l instrumentation because localized areas of higher contamination or " hot spots" I

may not be identified with the latter instrumentation. Therefore, TV Electric l has elected to classify the fixed area monitors as providing backup information to portable instrumentation which provides primary information for assessing the area environment. Thus, the CFSES accident monitoring design categorizes the fixed monitors as "E3s." The CPSES FSAR was updated in Amer dment 76, dated May 1,1989, to reflect this change.

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f Attachment to TXX-89253 May 19, 1989 Page 2 of 6 NRC Ouestion (2)

PRESSURIZER LEVEL: Table 032.110-4 identifies the'zero to 100% ranges as a deviation, yet does not define the extent of the deviation nor provide a basis for the acceptability of the deviation. Please document the actual range, in relation.to the top and bottom of the pressurizer vessel, and provide the basis for concluding that the provided range is acceptable.

TV Electric Resoonse (2)

The CPSES Unit 1 pressurizer consists of three sections: a cylindrical section approximately 513 inches in length, and hemispherical upper and lower heads with inner radii of 43 inches. The 0 to 100% range of the pressurizer level instrumentation monitors the entire length of the cylindrical section of the vessel and approximately 3 inches each of the hemispherical sections of the upper and lower heads. This is a deviation from the specified range of " top to bottom" as specified in Regulatory Guide 1.97 Rev. 2. However, associated control, protection and indication circuitry are within the CPSES monitored range of the pressurizer. Thus, CPSES meets the intent of the Regulatory-Guide, and considers the pressurizer range as an acceptable deviation.

NRC Ouestion (3)

PRESSURIZER RELIEF TANK TEMPERATURE: Table 032.110-1 identifies a range of 50 to 350 degrees, and Table 032.110-4 identifies a range of zero to 400 degrees.

Which is correct?

TV Electric Resoonse (3)

The correct range for pressurizer relief tank temperature is 50 to 3500F.

The FSAR will be updated in a future amendment to correct the range in 0&R Table 032.110-4.

NRC Ouestion (4)

STEAM GENERATOR LEVEL - WIDE RANGE: Identify the range in inches above the tube sheet. The instrumentation identified in Sheet 9 of Table 032.110-1 appears to meet the Category 1 requirements for this variable, yet it is identified as Category 2. Statements in Table 032.110-5 (#8 "not required" and #28 " backup variable") do not clarify the issue. Provide a concise description of the instrumentation provided. Justify any deviations from the limits of the recommended range. Specific deviations from the Category 1 recommendations should be discussed.

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Attachment to TXX-89253 May 19, 1989 Page 3 of 6-TV Electric Response (4)

-The attached Figure 1 provides the steam generator water level - wide range and narrow range tap elevations. Based upon NRC request, the utilization of the steam generator water level wide range instrumentation will be expanded to include a Type B Category 1 designation. The CPSES FSAR Table 0&R 032.110-4 notes a deviation from the Regulatory Guide 1.97, Revision 2, requirement for

" additional information" for wide range instrumentation. However based on further review, TU Electric has determined that the additional information requirements for the wide range instrumentation are satified by two diverse channels of auxiliary feedwater flow indication. In addition, the remaining Regulatory Guide Category 1 requirements are met. 'The CPSES FSAR will be updated in a future amendment to reflect this change.

NRC Ouestion (5)

IDENTIFICATION OF CATEGORY 2 INSTRUMENTATION: The applicant should provide justification'for not providing unique identification of Category 2 instrumentation as post-accident monitoring instrumentation.

TV Electric Resoonse (5)

In accordance with Regulatory Guide 1.97, Revision 2. CPSES Category 1 and 2 Type A, B and C accident monitoring instrumentation is uniquely identified on the control room main control board (HCB) with the exception of Steam Generator Blowdown: Condenser Off-Gas; and Plant Vent Stack radiation monitors and Containment Isolation Valve (CIV) Status indication.

The above radiation monitors are part of a computer based system in which information is displayed on demand on a CRT. Containment isolation valve status indication is provided by monitor light boxes (HLBs) located on the HCB. Utilization of the MLBs is incorporated in the CPSES plant specific Emergency Response Procedures. Through pattern recognition (i.e. all HLBs dark or lit), operators can quickly assess CIV status following an accident.

In addition, valve position indicating lights are provided at each CIV control switch in the control room. Like all safety-related control switches, CIV control switches are labelled according to the associated power supply (i.e.

train related color coding).

One objective of the CPSES human-f actors program is to optimize the control room main control board (HCB) coding / identification schemes to preclude operator confusion. In support of this objective, TV Electric has determined that it is inappropriate and impractical to provide additional identification for the radiation monitors and CIV status discussed above. It is the position of TV Electric that the CPSES coding / identification schemes meet the intent of Regulatory Guide 1.97, Revision 2, such that operators can easily discern which instruments are intended for use under accident conditions.

J Attachment to TXX-89253 May 19, 1989 Page 4 of 6 l

NRC Ouestion (6)

ISOLATION OF CATEGORY 2 INSTRUMENTATION: Isolation should be provided for all Category 2 instrumentation that provides signals to another system regardless of the power source involved. No single failure should be capable of failing more than a single channel of instrume cation.

TV Electric Response (6)

The evaluation of this issue is continuing. The final results will be provided in a later response by June 9, 1989.

NRC Ouestion (7)

INDICATION OF CATEGORY 1 INSTRUMENTATION: Category 1 instrumentation should have means for the continuous display or recording of the variable. Display on demand is not permitted in Revision 2 of Regulatory Guide 1.97. Verify that each_ channel of Category 1 instrumentation has a dedicated indicator, recorder, or display device. (We note the statement in the March 31, 1989 submittal that there are no deviations. This request is for clarification.)

TV Electric Resoonse (7)

Each accident monitoring channel of Category 1 instrumentation has a dedicated indicator, recorder or display device.

NRC Ouestion (8)

ENVIRONMENTAL 00ALIFICATION OF CATEGORY 2 INSTRUMENTATION: Define, in relation in your March 31, 1989 statement on environmental qualification of Category 2 instrumentation, the phrase "during the time it must serve its intended function." Does this mean that the instrumentation is environmentally qualified to 10CFR50.49 or located in a mild environment for the entire (indeterminate length of time) post-accident period?

TV Electric Resoonse (8)

Accident monitoring instrumentation, identified as Category 2 variables, per the guidance of Regulatory Guide 1.97, Revision 2, which are required to function during a design basis accident, but do not see a harsh environment during the time in which they are required to operate, are not environmentally qualified to 10CFR50.49. Instead, design documents will require an environmental qualification evaluation of these instruments if the environments in their areas are changed.

Attachment to TXX-89253 May 19, 1989

.Page 5 of 6 NRC Ouestion (9)

CONTAINMENT ATMOSPHERIC TEMPERATURE: FSAR Table 032.110-4, Sheet 4 indicates an instrument range of 0 to 360 degrees. Regulatory Guide 1.97 Revision 2 requires a~ range of 40 to 400 degrees. Clarify the deviation noted in Table 032.110-5.

TV Electric Resoonse (9)

The postulated peak vapor temperature inside containment for Unit 1 is 345 degrees fahrenheit. Thus, the CPSES instrument range is adequate to monitor the postulated temperatures for. normal plant operations, anticipated operational occurrences and accident' conditions. l NRC Question (10) H CONT ^INHENT PRESSURE : Regulatory Guide 1.97 Revision 2 recommends a containment pressure instrumentation range of 10 psia.to 3 times the design pressure. Table 032.110 1 indicates a range of 0 to 150 psig. Clarify the deviation for the lower end of the instrument range.

TV Electric Response (10)

The CPSES containment pressure - wide range instrument range is 0 to 150 psig.

In addition, the CPSES accident monitoring design includes containment pressure-- intermediate range instrumentation with a range of -5 to 60 psig.

The combined use of these two instruments is adequate to monitor the anticipated pressures for normal operation, anticipated operational occurrences and accident conditions. This deviation was previously accepted by the NRC-in SSER 12 Appendix T.

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Attachment to TXX-89253 1

May 19'i 1989 l- Page 6 of 6 FIGURE 1

[

NARROW RANGE (UPPER tap) AND nl0E RANCE (UPPER TAP)

A 8 l

TOP OF TUBE BUNDLE NARRCW RANGE - N5233.0' LOWER TAP Z=3 33 w:558.9 7-t IP A

Y:336.38' Xs353.05' r Ls7.08' T If IP V d

fuESHEET WIDE RANGE (LOWER TAP)

X: OfSTANCE FROM TOP OF TUBE SHEET TO NARROW RANGE - LOWER TAP Y= OlSTANCE FROM TOP OF TUBE SHEET TO TOP OF TUBE BUNOLE Z= DISTANCE FROM NARROW RANGE - LOWER TAP TO TOP OF TUBE BUNOLE N* OISTANCE FROM NARROW RANGE - LOWER TAP TO NARROW RANGE - UPPER TAP L= OlSTANCE FORM TOP OF TUBE SHEET 70 WIDE RANGE - LOWER TAP W= DISTANCE FROM WIDE RANGE - LOWER TAP f0 NOTES: WIDE RANGE - UPPER TAP

1. FIGURE IS NOT DRAWN TO SCALE.

2. FIGURE INDICATES NOMINAL VALUES AND IS TYPICAL FOR ALL LEVEL CHANNELS.

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