ML20012B310
| ML20012B310 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/06/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20012B307 | List: |
| References | |
| NUDOCS 9003140171 | |
| Download: ML20012B310 (4) | |
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SAFETY EVALUATION Bf THE OFFICE OF NUCLEAR REACTOR REGULATION i
RELATED TO AMENDMENT NO.140 TO FACILITY OPERATING LICENSE NO. DPR-53 BALTIMORE GAS AND ELECTRIC COMPANY i
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT 1
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DOCKET NO. 50-317 i
1.0 INTRODUCTION
By letter dated December 20, 1989, the Baltimore Gas and Electric Company (the licensee) proposed to amend the Technical Specifications (TS) of the Calvert Cliffs Nuclear Power Plant, Unit 1.
The proposed changes would disable the automatic start feature of the High Pressure Safety injection (HPSI) pump when in a plant condition requiring Low Temperature Overpressure Protection (LTOP) and require the safety injection tanks to be operable throughout mode 3, hot standby, operation. The licensee, by letters dated January. 23, February _2 and 14,1990, provided supplemental' information.
The January (LOCA) analysis using a different fission product decay heat 23, 1990, submittal provided the results of the loss of coolant accidents assumption which did not impact the conclusion reached from the initial analysis. The submittal also provided the consequences of a small break LOCA and the effect of manual startup of the HPSI pump during mode 3.
The February 2,1990, submittal provided further discussion of the consequences of a small break LOCA.
Finally, the February 14, 1990, submittal further clarified the impact and controls utilized during manual operation of the HPSI pump. This submittal also requested the footnote added to Technical Specification Table 3.S.J also be added to Section 3.5.3 with a clarifying statement related to manual operation of the HPSI pump. This clarification assures that the HPSI pump will be operated in a manner such that automatic initiation will not result in an LTOP event.
These supplemental submittals did not affect the proposed TS changes noticed in the Federal Register (55 FR 671) on January 8,1990 and did not affect the liTaTT1 proposed determination that no significant hazards would result from these changes.
The NRC staff has reviewed the application and the supporting documents and has prepared the following evaluation.
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2-i 2.0 EVALUATION LTOP is provided by the power operated relief valves (PORVs) on the pressurizer.
These PORVs are set at a pressure low enough to prevent violation of the 10 CFR 50 Appendix G pressure / temperature limits during heatup and cooldown should a reactor coolant system (RCS) pressure transient occur during low temperature operations. As presently written, the Calvert Cliffs LTOP system is enabled at RCS temperatures up to 330*F.
TS 3.5.3 currently requires that one HPSI pump be available for automatic operation while in mode 3.
The licensee has noted that if the HPSI pump were to inadvertently actuate while the LTOP system is enabled, the reactor vessel could be overpressurized beyond the 10 CFR 50, Appendix G, limits. The licensee has proposed a modification to TS Table 3.3-3 and Section 3.5.3 to specify that the required operable HPSI pump will be placed in " pull-to-lock" when the average RCS temperature is less than or equal to 350'F, which will not allow the pump to automatically start. To maintain RCS inventory in the event of a large break loss of coolant t
accident (LBLOCA) while the HPSI pump is unavailable for automatic start, another specification, TS 3.5.1.b. requires minimum Safety injection Tanks (SITS) volume to be maintained while in Mode 3 when the pressure is greater than 1750 psia.
The licensee has proposed a change which will require the SITS to be operable while in Mode 3 regardless of the pressure.
In support of the proposed changes, the licensee provided the results of a postulated LOCA analysis to determine the SITS pressure and volume needed to fill the reactor vessel following a LBLOCA and the minimum time available to initiate additional RCS makeup flow to maintain core heat removal.
In response' to a staff concern with one of the analysis assumptions, the licensee provided the results of an evaluation with a
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revised assumption regarding decay heat.
The results of the analysis indicted at least 18 minutes are available for operator action in the event of a LBLOCA. The staff finds the licensee's analysis and results regarding LBLOCA acceptable.
The licensee also has procedures available to the operator for a small break loss of caolant accident (SBLOCA) during mode 3.
To quantify the l
time period for operator action, the licensee provided the results of conservative. bounding estimates which demonstrate that there is at least an equivalent margin to LOCA acceptance criteria as that found in the facility Final Safety Analysis Report for the same event. The operator would identify the event through changes in containment conditions, such as; pressure, temperature, and sump level.
Upon positive identification of reactor vessel inventory loss by sump level alarms, or containment pressure or temperature alarms which would occur prior to reactor vessel water level reaching the leyc1 of the break location, the operator would then manually initiate HPSI Injection from the control room, thus minimizing the required operator action time.
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i The results of the licensee's analyses demonstrated that:
(1) for a large break LOCA sufficient capacity is available in the SITS to provide core cooling in the absence of HPSI injection for 18 minutes, and (2) for a SBLOCA, the time identified for recognition of the existence of the break and manual initiation of a HPSI pump is longer than 18 minutes by a time period dependent upon break size. However, the l
operator has sufficient time for manual initiation of a HPSI pump following a SBLOCA; thus, the current acceptance criteria for LOCA un be met.
These results show that protection against a postulated LOCA of all break i
sizes can be maintained based on the proposed changes. Based on these results, the staff finds the response acceptable.
The addition of a footnote to Item 1, Table 3.3-3 of the Technical Specification which states, "When T-avg 350'F, the OPERABLE high pressure safety injection pump will be placed in ' pull-to-lock' and will not start automatically," assures the pump will not automatically start when conditions could result in an LTOP event. The change to Section 3/4.5 requiring the SITS to be operable while in mode 3, regardless of system pressure, assumes that adequate water n available during a postulated LOCA until a HPSI pump is manually started.
The changes are supported by suitably conservative analyses to demonstrate that adequate protection against a postulated LOCA is provided during operational mode 3 when the average RCS temperature is less than or equal to 350*F. Also the proposed changes will not compromise 10 CFR Part 50, Appendix G, limits due to an inadvertent automatic actuation of a HPSI pump. Thus, the staff finds the proposals acceptable.
The request was not clear on manual use of the HPSI pump under required conditions, such, as mitigation of a SBLOCA during mode 3.
Such use would be conducted in accordance with an Abnormal Operating Procedure (A0P-2A).
To accommodate this need, the licensee, by letter dated February 14, 1990, proposed a clarification to TS 3.5.3, ECCS Subsystems. The clarification includes a footnote to Item a of Limiting Condition for Operation 3.5.3, page 3/4 5-6, which states, "When T-avg 350'F, the OPERABLE high pressure safety injection pump will be placed in Pull-to-Lock and will not start automatically. Manual use of the high pressure safety injection pump will be conducted in accordance with approved procedures." The approved procedures were previously provided and reviewed by the staff in conjunction with the initial request. This clarification assures the inadvertent automatic initiation will not result in a LTOP event. The staff finds this additional change appropriate and acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of the facilities' components located within the restricted areas as defined in 10 CFR 20. The staff has determined that this amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there i
has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10CFRSection51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLllSION We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposed manne., and (2) public such activities will be conducted in compliance with the Commission's regulations and the iscuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated: March 6, 1990 PRINCIPAL CONTRIBilTIORS:
M. McCoy D. Mcdonald L
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