ML20116E510
| ML20116E510 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 02/23/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20116D885 | List:
|
| References | |
| FOIA-96-237 NUDOCS 9608060021 | |
| Download: ML20116E510 (5) | |
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L ENCLOSURE 1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l
RELATING TO TECHNICAL SPECIFICATION CHANGES FOR HPSI OPERABILITY IN M00E 3 BALTIMORE GAS AND ELECTRIC COMPAhf CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT 1 DOCKET NO. 50-317
1.0 INTRODUCTION
By letter dated December 20, 1989, the Baltimore Gas and Electric Company (the licensee)proposedtoamendtheTechnicalSpecifications(TS)oftheCalvert Cliffs Nuclear Power Plant, Unit 1.
The proposed change would disable the automatic start feature of the Hioh Pressure Safety Injection (HPSI) pumps when in a plant condition requiring Low Temperature Overpressure Protection (LTOP). The licensee, by letters dated January 23, 1990 and February 2, 1990, provided responses to staff requests for additional information. An additional TS change related to the original proposal was requested by letter dated February 14, 1990.
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 cccur durino 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 the HPSI purps be available for automatk operation while in Mode 3.
The licensee has noted that,1f a HPSI pump were to inadvertently actuate while the LTOP s/ stem is enabled, the reactor vessel 9608060021 960731 PDR FOIA C,,
-DINIC0L96-237 PDR
2 could be overpressurized beyond the 10 CFR 50 Appendix G limits. The licensee has proposed a modification to TS Table 3.3-3 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. To maintain RCS inventory in the ennt of a large break loss of coolant accident (LBLOCA) while the HF3I pump is unavailable, another specification, TS 3.5.1.b requires a minimum Safety Injection Tank (SIT) volume to be maintained while in Mode 3.
No change to TS 3.5.1.b is required or proposed.
In support of this change, the licensee provided the results of a postulated LOCA analysis to detemine the SIT 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 cne of the analysis assumptions, the licensee provided the results of a new evaluation with a revised assumption regarding decay heat. The results of this analysis showed that at least 13 minutes are available for operator action in the event of a LBLOCA. The staff finds the licensee's analysis and results regarding LBLOCA
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acceptable.
In response to the staff request, the January 23 submittal also discussed procedures available to the operator for a small break loss of coolant accident (SBLOCA) during Mode 3.
To quantify the time period for operator action, the licensee by letter dated February 2,1990, 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 losshsump level alams, or containment pressure or temperature alarms which would occur prior to reactor vessel water level reaching the break location, the operator would then initiate HPSI injection through actions within the control room, thus minimizing the required operator action time.
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The results of the licensee's analyses demonstrated that I
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(1) for a large break LOCA sufficient SIT capacity is available to provide j
core cooling in the absence of HPSI infection for 18 minutes, and I
j (2) for a SBLOCA, the time identified for recognition of the existence of the i
break and manual initiation of a HPSI pump is longer than 18 minutes by a j
time period dependent upon break size. However, the operator has sufficient time for manual initiation of a HPSI pump following a SBLOCA l
and current acceptance criteria for LOCA can be met.
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l These results show that protection against a postulated LOCA of all break I
sizes can be maintained under the proposed change. Based on these results, the staff finds the response acceptable.
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The original TS change proposed by the licensee is the addition of a footnote to Item 1, Table 3.3-3, page 3/4 3-11 which states "When T-avg $ 350*F, the 1
OPERABLE high pressure safety injection pump will be placed in ' pull-to-lock' l
and will not start automatically." The change is supported by suitably
. conservative analyses to demonstrate that adequate protection against a j
postulated LOCA is provided during operational Mode 3 when the average RCS j
temperature is less than or equal to 350'F. Also the proposed change will not j
compromise 10 CFR Part 50 Appendix G limits due to an inadvertent actuation of l
- a HPSI pump. Thus, the staff finds the prooosal acceptable.
During the review of the December 20, 1989 proposed TS change, it was noted that the request does not allow the flexibility for 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 Abnomal Operating Procedure (AOP-2A). To accomodate this need, the licensee, by letter dated February 14, 1990 proposed a change to TS 3.5.3, ECCS Subsystems, for Calvert Cliffs Unit 1.
The proposal is to add a. footnote to Item a. of Limiting Condition for
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Operation 3.5.3, page 3/4 5-6 which states "When T-avg 6 350'F. the OPERAP,LE
i 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 provided in the January 23, 1990 submittal and were reviewed by the staff in conjunction with the initial request. The staff finds this additional change appropriate and acceptable.
In a related matter, a separate page for Calvert Cliffs Unit 2 TS 3.5.3 is needed for editorial purposes, since this approval does not extend to the second unit.
3.0 CONCLUSION
We have reviewed the results of the supporting analyses for the proposed TS changes and have concluded that the changes are acceptable.
We have also concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not ba endangered by operation in the proposed manner, and (2) such activities will
!>e conducted in compliance with the Commission's regulations, and issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
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4 ENCLOSURE 2 SYSTEMATIC ASSESSMENT OF LICENSEE PERFORMANCE
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FACILITY NAME Calvert Cliffs Unit 1 4
SUMMARY
OF REVIEW Baltimorp Sss and Electric Company, the licensee of Calvert Cliffs Unit 1, has submitted an application to change the Technical Specifications to disable the automatic start feature of the HPSI pumps when in a plant condition requiring Low Temperature Overpressure Protection.
The Reactor Systems Branch (SRXB) has reviewed the proposed change and concludes that the licensee proposed changes are acceptable.
NARRATIVE DISCUSSION OF LICENSEE PERFORMANCE - SAFETY ASSESSMENT /00ALITY VERIFICATION The licensee showed a general understanding of the technical issues from a safety standpoint and used acceptable approaches to resolve them. The
~ licensee took timely action in response tc the staff request for additional information.
AUTHOR:
M. McCoy DATE:
2/22/90