ML20207P072

Safety Evaluation Supporting Conformance to Reg Guide 1.97 W/Noted Exceptions

ML20207P072
Person / Time
Site:	Calvert Cliffs
Issue date:	01/06/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20206H539	List: ML20206H535 ML20207P072
References
RTR-REGGD-01.097, RTR-REGGD-1.097 GL-82-33, NUDOCS 8701150006
Download: ML20207P072 (4)

Text

.-

usur

[g UNITED STATES

[

g NUCLEAR REGULATORY COMMISSION tj WASHINGTON, D. C. 20555

's.,...../

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION BALTIMORE GA5 AND ELEU MIC COMPANY CALVERT CLIFF 5 NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET N05. 50-317 AND 50-318 CONFORMANCE TO REGULATORY GUIDE 1.97 INTRODUCTI0f: AND $UMMARY Baltimore Gas and Electric Company was requested by Generic Letter (GL) 82-33 to provide a report to the NRC describing how the post-accident monitoring instru-mentation meets the gui.delines of Regulatory Guide (R.G.) 1.97 as applied to emergency response facilities. The licensee responded to the generic letter on December 1,1984. Additional information was provided by letter dated j

February 21, 1986.

A detailed review and technical evaluation of the licensee's submittals were performed under contract by EG8G Idaho, Inc., with general supervision by the NRC staff. This work was reported by EG&G in the attached Technical Evaluation Report (TER), "Confomance to Regulatory Guide 1.97, Calvert Cliffs Nuclear Power Plant Unit Nos. I and 2," dated April 1986. The staff has reviewed this report and concurs with the conclusion that the licensee either conforms with, or is justified in deviating from, the guidance of Regulatory Guide 1.97 for each post-accident monitoring variable except for the variables a) accumulator tank level and pressure; b) containment sump water level (narrow range);c)containmentsumpwatertemperature;d)componentcoolingwaterflow to the ESF system; e) RCS soluble boron concentration; f) radiation level in circulating primary coolant; and g) degrees of subcooling.

EVALUATION CRITERIA Subsequent to the issuance of GL 82-33, the NRC held regional meetings in February and March 1983 to answer licensee and applicant questions and concerns regarding the NRC policy on R.G. 1.97. At these meetings, it was noted that the NRC review would only address exceptions taken to the guidance of R.G. 1.97.

Further, where licensees or applicants explicitly stated that instrument systems conforned with the provisions of the R.G., it was noted that no further staff review would be necessary. Therefore, the review performed and reported by EG&G only addresses exceptions to the guidance of R.G. 1.97. This Safety Evaluation addresses the licensee's submittals based on the aforementioned review policy and the conclusions of the review as reported by EG&G.

hh P

EVALUATION The staff has reviewed the evaluation performed by the consultant contained in the enclused TER and concurs with its bases and findings. The licensee either conforms tu, or has provided an acceptable justification for deviations from, the guidance of Regulatory Guide 1.97 for each post-accident monitoring variableexceptforthevariablesa)accumulatortanklevelandpressure,b) containment sump water level (narrow range), c) containment sump water tempera-ture and d) component cooling water flow to the ESF system.

a)

R.G. 1.97 recommends that Category 2 instrumentation be provided to monitor the accumulator tank level and pressure. The licensee has provided instrumentation which conforms to the criteria for Type D, Category 2, variables with the exception of environmental qualification.

The licensee states that the accumulators are a passive system and that action takes place within 1 minute of the accident or well after safety injection, depending upon the leak size.

In either case, operator action is rot required to mitigate the consequences of the postulated accident.

Also, the signals from accumulator tank level and pressure instrumentation are not used as inputs to any automatic safety function. While the staff agrees with the licensee that this is a passive system and that the variables are not used for automatic initiation of a safety function, it believes that this instrumentation should be provided to permit the operator to determine if the plant safety functions (accumulator discharge) are being performed.

In this regard, the staff finds the licensee's proposed exception to the guidelines of R.G. 1.97 unacceptable.

b)

R.G. 1.97 recommends that Category 2 narrow range instrumentation be provided to monitor the containment sump level. The licensee has provided this instrumentation that confonns to the criteria for Type B, Cateaory 2, variables with the exception of environmental qualification.

The licensee states that the narrow range sump level instrumentation is used only during normal plant operations and that the qualified wide range instrumentation provided for the containment is all that is necessary for post-accident monitoring. The range of the wide range instrumentation does not start until the water level is 9 inches above the containment floor. Thus, early detection of loss of coolant in the primary system cannot be obtained from the wide range sump level instru-ments. Since the narrow range instrumentation is useful for following the course of some postulated accidents, the staff finds that the environmentally oualified instrument must be provided for this variable.

Based on this, the staff finds the licensee's proposed exception to the guidelines of R.G. 1.97 unacceptable.

1 c)

R.G. 1.97 recommends that instrumentation be provided to monitor the containment sump water temperature. The licensee has not provided instrumentation for this variable. The licensee states that the minimum l

NPSH requirements are not dependent on the sump water temperature.

Therefore, this variable is not used in the management of design basis 4

accidents. While the staff agrees that the NPSH requirements are ade-quately allowed for, this is not the only reason for the instrumentation.

Sump water temperature is useful in determining the proper operation of the containment cooling system.

a this regard, the staff finds the licensee's proposed exception to the guidelines of R.G. 1.97 unacceptable.

d)

R.G. 1.97 recommends that instrumentation be provided to monitor the cooling water flow to ESF system. The design does not provide for flow instrumentation for this variable and the licensee has not yet justified this exception. A commitment is needed from the i

licensee that the flow instrumentation is to be installed.

The review of the acceptability of the instrumentation provided for monitoring the following variables was not conducted in this study as it was performed in the evaluation of the licensee's compliance with Items II.B.3 and II.F.2. of NUREG-0737:

a RCS soluble boron concentration b

radiation level in circulating primary coolant c

degrees of subcooling.

CONCLUSION

-Based on the staff's review of the attached Technical Evaluation Report and the licensee's submittals, it finds that the Calvert Cliffs Nuclear Power Plant, Unit Nos. I and 2, design is acceptable except as noted below with respect to conformance to R.G. 1.97, Revision 3.

a)

The staff recognizes that the operator can infer from either level or pressure that the accumulator is injecting borated water into the reactct i

coolant system. Therefore, it is the staff's position that the licensee designate either level or pressure as the key variable to determine accumulator discharge and provide instrumentation for that variable that is environmentally qualified to the requirements of 10 CFR 50.49.

It is also the staff's position that the licensee shall install, and have l

operational for both Units 1 and 2, qualified accumulator tank level or i

pressure instrumentation at the first scheduled outage of sufficient duration, but no later than startup following the spring 1988 Unit I refueling outage.

I i

b)

It is the staff's position that the information provided by the narrow range sump level variable is useful to an operator in the evaluation of i

some accident conditions.

Instrumentation that meets the enviromrental i

qualification requirements of 10 CFR 50.49 for harsh environments should i

be supplied for this variable.

It is also the staff's position that the licensee shall install, and have operational for both Units 1 and 2, qualified narrow range containment sump instrumentation at the first scheduled outage of sufficient duration, but no later than startup following the spring 1988 Unit I refueling outage.

i 4

' c)

It is staff's position that containment sump temperature is useful to an operator in determining that the containment cooling system is functioning properly during the post-accident mode of operation.

It is also the staff's position that the licensee shall install environmentally qutlified containment sump temperature instrumentation, or identify suitable qualified alternate instrumentation that will allow a quantitative look at the heat removal from tne containment sump, and have this instrumentation operational for both Units 1 and 2, at the first scheduled outage of sufficient duration, but no later than startup following the spring 1988 Unit I refueling cutage.

d)

In the licensee's original response of December 1,1984, the licensee stated that a review would be conducted to determine if this variable was needed at this station.

In Reference 5 to the attached TER, the licensee states that this review is still ongoing. The staff concludes that adequate time has elapsed since the original response to make a deter-mination and provide justification for not installing the flow instrumen-tation.

It is the staff's position that qualified instrumeatation be installed and operational for both Units 1 and 2 for the component cooling water flow to the ESF system, at the first scheduled outage of sufficient duration, but no later than startup following the spring 1988 Unit I refueling outage.

e)

The instrumentation for monitoring RCS soluble boron concentration and the radiation level in circulating primary coolant was found to be acceptable in the Commission review, dated June 24, 1983, of the licensee's compliance with NUREG-0737 Item II.B.3, titled " Safety Evaluation of Post-Accident Sampling System of Calvert Cliffs Nuclear Power Plant."

f)

The acceptability of the instrumentation provided for monitoring degrees of subcooling is currently under evaluation through the Comission review of the licensee's response to the NRC Generic Letter No. 82-28,

" Inadequate Core Cooling Instrumentation System."

Principal Contributors:

H. Garg S. McNeil Date: January 6, 1987

Attachment:

TER