ML20235P008
| ML20235P008 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/10/1987 |
| From: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20235P009 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM GL-82-28, NUDOCS 8707200301 | |
| Download: ML20235P008 (6) | |
Text
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l Q BALTIMORE GAS AND ELECTRIC -
l CHARLES CENTER P. O. BOX 1475 BALTIMORE, MARYLAND 21203 l
JOSEPH A.Tj ERNAN '
l Vict PatSIDENT
' NUCLEAR ENcnov -
- July 10,1987 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos. I and 2; Docket Nos. 50-317 & 50-318 Reauest for Amendment REFERENCES l(a) NUREG-0737, dated October 31, 1980, Post TMI Requirements, Item II.F.2 (b) Generic Letter 82-28, dated December 10, 1982, Inadequate Core Cooling Instrumentation System (c) Letter from Mr. A. E. Lundvall, Jr. -(BG&E), to Mr. J. R. Miller (NRC), dated April 10, 1984, Reactor Vessel Level Monitoring System (d) Letter from Mr. S. A. McNeil (NRC), to Mr. J. A. Tiernan (BG&E),
dated February 9,1987, Safety - Evaluation of the Inadequate Core Cooling System (e) Generic Letter 83-37, dated November 1,1983, NUREG-0737 Technical Specifications (f) Letter from Mr. Dennis M. Crutchfield (NRC), to Mr. R. W. Wells (CE), dated October 28, 1086, Reactor Vessel Level Monitoring System Technical Specification Safety Evaluation l
Gentlemen:
1 The Baltimore Gas and Electric Company hereby requests an Amendment to its Operating Licensing Nos. DPR-53 and DPR-69 for Calvert Cliffs Unit Nos.1 & 2, respectively, with
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the submittal of the proposed changes to the Technical Specifications.
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Document Control Desk July 10,1987 Page 2 CHANGE (BG&E FCR 87-25)
Change pages 3/4 3-41, 3-41a, 3-42, B 3/4 3-3, and 6-18a of the Unit I and 2 Technical Specifications as shown on the marked up copies attached to this transmittal.
INTRODUCTION The NRC, in accordance with References (a) and (b), has required utilities to install instrumentation for the detection of inadequate core cooling. As part of the required instrumentation, we have installed a Reactor Vessel Level Monitoring System (RVLMS) on both Units. Unit 2 RVLMS was installed in fall 1985; Unit 1,
in fall 1986. This change incorporates the RVLMS into the Post-Accident Instrumentation section of the Technical Specifications. We propose that the NRC review these Technical Specifica-tions for both Units I and 2,
implementing Unit 2's Technical Specification upon completion of your review. The implementation date for Unit l's Technical Specifica-tion will be finalized with NRC's Project Manager for Calvert Cliffs, following the standard refueling interval allowed for system testing.
BACKGROUND As discussed in Reference (c), the RVLMS uses the Combustion Engineering (CE) Heated Junction Thermocouple (HJTC) system to monitor reactor coolant inventory during the saturation conditions that exist prior to the loss of a sufficient amount of coolant to uncover the top of the active core. The level range extends from the top of the vessel down to the top of the fuel alignment plate. Based on a generic study done for CE-designed plants, the response time is short enough to track vessel level during small break Loss of Coolant Accident events. The level resolution is sufficient to show the initial level drop, the key locations near the hot leg elevation, and the lowest levels just above the fuel alignment plate. This provides the control room operator with additional information to: 1) track the event, 2) assess the functioning of automatic equipment, and 3) detect the consequences of mitigating actions.
The RVLMS consists of two independent safety channels. Each channel consists of a probe assembly, support tube, pressure boundary modifications, signal processing equip-ment, and an operator interface. Each instrument channel is manufactured into a probe assembly consisting of eight HJTC sensors.
The eight sensors are physical y independent and located at eight levels in the vessel, from the reactor vessel head to the fuel alignment plate. The basic principle of system operation is the detection of a temperature difference between adjacent heated and unheated thermocouple. In a fluid with relatively good heat transfer properties (water), the temperature difference between the adjacent thermocouple is very small. In a fluid with relatively poor heat transfer properties (steam), the temperature difference will be large.
The HJTC probe holder support tubes provide the guidance and support for the probe assemblies. The support tubes are located in two vacated part length control element assembly / shrouds. The probe assembly pressure boundary penetration is designed such that the assembly can be removed or installed through the penetration without removing the reactor vessel head.
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%. Document Control Desk
& uly 10,.1987 J
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Page 3 The following operator interfaces are available:
The mrlin ' control board display consists of eight lights per channel
. to reflect the-status of each pair of HJTC AL trend recorder provides a permanent trend history of reactor level The plant computer alarms to indicate " system malfunctions" and " low level" in the reactor vessel A digital display is provided at the signal processor cabinet to display reactor level percent.
>s1 The NRC recendy reviewed the RYLMS as - part of their safety evaluation of the inade-
. que,Cor'e' Cooling (ICC) Instrumentation system for Calvert ' Cliffs Units I and 2:
(ReferFrice d). The ICC Instrumentation system was found to meet the requirements of item li.F.2 of NUREG-0737. This acceptance, however, was contingent upon NRC review and approval ~ of several open items (e.g., computer, upgrades, procedure and operator training,' etc.). Technical Specifications for the RVLMS, one of the "open ' items," are provided herein.
DISCUSSION Guidance Technical' Specifications. for. the. Reactor Vessel Level Monitoring System were originally provided ' to utilities in ~ Reference (e). These NRC proposed Technical Specifications suggested a plant shutdown within seven days with less than two probes OPERABLE, and within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> with less than one probe OPERABLE. The Combustion Engineering Owners' Group (CEOG) Technical Specification Subcommittee discussed with the NRC _ the safety significance of not having the' RVLMS available, and concluded the
. suggested Technied Specifications were too restrictive. A mutually. agreed upon solu-tion was reached; and Arizona Public Service Co. (Palo Verde Unit 1) submitted, and the NRC approved, Technical Specifications similar to this proposed change. Additionally, the NRC recently completed their review of the CEOG recommended RVLMS Technical Specifications. The NRC deemed that these Technical Specifications were acceptable (Reference f).
The CEOG Technical Specifications require that with one channel inoperable, either the cystem is restored to OPERABLE status within seven days or a Special Report is submitted to ' the Commission detailing plans for restoring the system to OPERABLE
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. status.' With the number of OPERABLF channels two less than required, operation may continue unts the next scheduled refueling provided 2n alternate method of monitoring I
for core. and reactor. coolant system voiding is available. Finally, a Special Report must be submitted to the NRC detailing the cause of the inoperability and the schedule for restoring the system to OPERABLE status.
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Document Control Desk
' July 10,- 1987 1
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l We have 'made two. minor changes to the standard RVLMS Technical Specifications (Reference f). First. the' words "for core and a reactor coolant system voiding" were 3
substituted for "the reactor vessel inventory" in Action Statement 35.1, resulting in:
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" Initiate an alternative method of monitoring for core and reactor coolant system voiding."
TheseL words are' more technically correct since the Emergency Operating Procedures (EOPs) give guidance in determining whether voids exist. The EOPs also provide instructions to reduce or eliminate voids should they occur. The " alternate method" of m
mrnitoring for core and reactor coolant system voiding was our primary method prior to s
the RVLMS modification. This alternate method utilizes various instruments (e.g.,
pressurizer level, subcooling. Th Tc, core exit thermocouple) to provide core and reactor coolant system voiding information.
The second change to the Standard. RVLMS Technical Specifications consists of.;ubstitut-ing the words "at least one channel" for the "the system" in Action Statement 35.3, resulting in:
" Restore at least one channel to OPERABLE status at the next scheduled refueling."
These words remove the ambiguity of whether the " system" is comprised of one, or both, RVLMS channels. It is noted ir. the Technical Specification bases that should both channels be inoperable - repairs to both channels shall be attempted during the next refueling outage.-
In conjunction with the addition of RVLMS to Technical Specification Table 3.3-10, an administrative change is proposed for the Unit i Technical Specification pages. This change, shown on the attached marked up pages, renumbers the Unit I listing of Post Accident instrumentation to achieve consistency with the Unit 2 pages. Additionally, a typographical error is corrected on Unit 2 page 3/4 3-41.
DETERMIN ATION OF SIGNIFICANT H AZ ARDS This proposed change has been evaluated against the standards in 10 CFR 50.92 and has been determined to involve no significant hazards considerations, in that operation of the facility in accordance with the proposed amendment would not:
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Document Control Desk July 10,1987 Page 5 l
(i) involve a significant increase in the probability or consequences of an accident previously evaluated; or The Reactor Vessel Level Monitoring System has been installed to enhance the ability of the plant operator to diagnose the approach to, and recovery from, inadequate core cooling. These instruments are ' being incorporated in the Technical Specifications at the request of the NRC.
1 The instruments are not required to meet the accident analyses, nor to safely shut down the plant.
(ii) create the possibility of a new or different type of accident from any accident previously evaluated; or The failure of this equipment would not result in any unanalyzed accident.
The equipment is simply passive monitoring instrumentation. Although the RVLMS has been utilized in the Emergency Procedures for corroboration of selected indications, no change to normal operating procedures is involved. The RVLMS is intended solely to enhance the ability of the operator to manage accidents and transients by providing the operator with additional corroborative information. Therefore, no new or different kind of accident from those previously evaluated are created by this proposed change.
(iii) involve a significant reduction in a margin of safety.
The proposed change provides an assurance of availability of an additional means for monitoring the proper functioning of the engineered safety features system in maintaining the core cooling function. Redundant channels of environmentally qualified instrumentation are provided to assure that the information presented to the plant operators accurately reflects the trend in level of reactor coolant in the vessel. The change does not involve a reduction in a margin of safety.
S_AFETYCOMMITTEE REVIEW l
These proposed changes to the Technical Specifications and our determination of signifi-j cant hazards have been reviewed by our Plant Operations and Off-Site Safety Review Committees, and they have concluded that implementation of these changes will not I
result in an undue risk to the health and safety of the public.
- Document Control Desk July.10 1987.-
- Page 6 FEE DETERMINATION 1
Pursuant to'.10 CFR 170.21, we are including BG&E Check No. (1141142) in the amount of.
- 5150.00 to the NRC
- to cover, the application fee for this request.
Very truly yours, Nh STATE OF MARYLAND
' TO WIT:
COUNTYOFCALVERT Joseph A; Tiernan, being duly sworn states that he is Vice President of the Baltimore
- Gas and Electric Company, a corporation of the State of. Maryland; that he provides the foregoing ' response for the purposes therein set forth; that 'the statements made are
. true and correct to the best of his knowledge, information, and belief; and that he was authorized to provide the response on behalf of said Corporation.
WITNESS my Hand and Notarial Seal:
d.
Notary Public My Commission Expires:
/, /9id LDate' JAT/BEH/ dim Attachments cc:
D. A. Brune, Esquire J. E.
Silberg, Esquire Ri A.Capra,NRC S. A.McNeil,NRC W. T. Russell, NRC T. Foley/D. C. Trimble, NRC T. Magette, DNR
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