ML20199B432
| ML20199B432 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 10/28/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20199B424 | List: |
| References | |
| NUDOCS 9711180320 | |
| Download: ML20199B432 (8) | |
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t UNITED STATES
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NUCLEAR REGULATORY COMMISSION l
wAemcoToN, D.C. 30eeH001
\\*****/g SAFETY EVALUA~ ION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMELDMENT NO.106 TO FACILITY OPERATING LICENSE NO. NPF-S7 EUBLIC SERVICE ELECTRIC & GAS COMPANY ATLANTIC CITY ELECTRIC COMPANY HOPE CREEK GENERATING STATION DOCKET NO. 50-354 i
1.0 HIBODUCTI0fl By letter dated May 19, 1997, as supplemented by letter dated August 25, 1997, the Public Service Electric & Gas Company (the licensee) submitted a request for changes to the Hope Creek Generating Station, Technical Specifications (TSs). The proposed amendment would change TS 3.7.1.3, " Ultimate Heat Sink,"
to raise the minimum allowable ultimate heat sink (VHS) water level from 76 feet to 80 feet, lower the naximum allowable UHS teiaperature from 88.6 'F to 85 'F and reflect that continued plant operation to a UHS temperature of 87 'F depends upon the association of UHS temperature And safety system availability. The associated Surveillance Requirement, TS 4.7.1.3, would be changed to decrease the river water temperature, at which increasing temperature surveillance is required, from 85 'F to 82 'F.
The requirements of TS 3.7.1.1, " Safety Auxiliaries Cooling System (SACS)," TS 3.7.1.2,
" Station Service Water System (SSWS)," and TS 3.8.1.1, " Electrical Power Systems," vould be revised to reflect the revised TS 3.7.1.3.
In addition, the Bases for 3/4.7.1, " Service Water Systems," would be appropriately revised. The August 25, 1997, letter provided clarifying information that did not change the initial proposed no significant hazards determination.
2.0 DISCUSSION Section 9.2.1 of the Hope Creek Generating Station (l; CGS) Updated Final Safety Analysis Report (UFSAR) describes the Station Service Water System (SSWS).
Normally, the SSWS circulates water, via two of four ISWS pumps, from the Delaware River (the ultimate heat sink) to the heat exchangers associated with the Safety Auxiliary Cooling System (SACS). Other nonessential heat loads, including the Reactor Auxiliary Cooling System (RACS), are cooled by the SSWS under normal conditions. 'Jater from the SACS heat exchangers is normally discharged to the station cooling tower via a nonSeismic Category I flow path.
In the event that this normal flow path is unavailable, water is discharged
. directly to the plant yard via the Seismic Category I emergency overboard (E0B) lines. The SACS is designed to provide cooling water to the engineered safety features (ESF) equipment, including the residual heat removal (RHR) heat exchangers, during normal operation, nonnal plant shutdown, loss of offsite power (LOP), and a loss-of-coolant accident (LOCA).
9711180320 971028 i
PDR ADOCK 05000354 9
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p By letter dated May 10, 1996, the licensee submitted Licensee Event Report (LER)96-015.
In that LER, the licensee reported that following a loss of the normal discharge path, with the UHS at its TS 3.7.1.3 limit of 88.6 'F, flow through the E0B discharge lines may not be sufficient to maintain the SACS heat exchanger outlet temperature below the design limit of 95 *F during certain postulated design basis conditions. The normal discharge path is assumed to be lost following a Safe Shutdown Earthquake (SSE) or a high wind event, which is assumed to cause collapse of the cooling tower. As reported in the LER, the original design calculations were deficient in that they did not adequately take into account the hydraulic losses in the overboard discharge path. The purpose of the licensee's May 19, 1997, proposed TS changas,assupplementedbyletterdatedAugust 25, 1997, is to establish a maximum allowabie UHS temperature limit based upon equipment availability and a revised analysis that assumes the SSWS discharge flow path is through the E0B lines. As a result of the revised analysis, the proposed TS change would also increase the minimum required UHS water level.
3.0 EVALUATION The May 19, 1997, application for license amendment provides a systems reanalysis of the SSWS and SACS operating conditions with the goal of establishing UHS limits and equipment operability requirements.
The actions required of operaters to support normal and post-accident mitigation are also considered.
3.1 Systems Reanalysis The licensee performed the systems reanalysis by constructing nodal temperature / flow models of the SSWS and SACS. These models were " bench marked" using existing data from SSVS and SACS testing.
Table 9.2-3, "STACS [ Safety and Turbine Auxiliary Cooling System] Equipment Design Parameters," of the HCGS UFSAR indicates that the SACS heat exchangert have a maximum design outlet temperature of 95 'F.
Using the 95 *F limit, and the nodal temperature / flow models, the licensee performed a series of calculations to determine UHS values for various system configurations. The calculat' as assume that the SACS heat exchangers are at a discharge temperature 95 'F and that:
The SSWS Pump flow is the minimum permitted under the Inservice Test Program.
The SSWS strainers are 75% clogged and the SACS heat exchangers are fouled in accordance with design basis conditions.
Discharge is via the Seismic Category I E0B lines.
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' The river water level is PSE&G datum elevation (el.) 80 feet.
Section 9.2.1.5 of the HCGS UFSAR indicates that a river water level of al.
76 feet provides the SSWS pumps of a net-positive suction head (NPSH) of 27 feet.
Flow through the RACS is assumed except during the LOCA scenario (RACS is automatically isolated in the LOCA scenario).
The calculations determined the maximum allowable UHS temptrature following a LOCA with Loss of Instrument Air (LOCA/LIA) and following a loss of Offsite Power with a Safe Shutdown Earthquake (LOP /SSE). The calculations also considered a wide rar.?e of equipment failures in the SSWS and SACS together with any operator actions in certain scenarios. The equipment failures were considered from the design hsis state (initially all safety systems operable) and from equipment configurations permitted by Allowed Out-of-Service Times (A0T) permitted by the TS (initially. some equipment is inoperable).
The results of the calculations indicated that the most limiting post-accident UHS temperature was 85 *F for feilure of an E0B valve with consequent loss of an E0B discharge path. Operator action (e.g., isolation of the spent fuel pool cooling) was also credited for the 85 *F UHS value.
The calculations also indicated that indefinite operation up to a UHS temperature of 87 'F was acceptable provided that both E0B discharge valves were open, all SSWS and SACS pumps, and Emergency Diesel Generators (EDGs) are operable and credit is taken for operator action in certcin accident scenarios.
In addition, operation up to a UHS temperatura of 87 *F requires that SACS be operated with no cross-connected loads other than those that are automatically isolated under post-accident conditions, she NRC staff review of the licensee's calculations indicate that the assumptions of the initial conditions and the accident scenarios are suitably conservative.
The treatment of operator responses, credited for certain accent scenarios is addressed in Section 3.2 herein.
3.2 Operator Responses The staff used the following guidance relevant to manual operator actions and times to complete its evaluation of the licer.see's submittals: Generic Letter 91-18, "Information to Licensees Regarding Two NRC Inspection Manual Sections on Resolution of Degraded and Nonconforming Conditions and on Operability (1991)," and American National Standards Institute /American Nuclear Society (ANSI /AWS)-58.8, " Time Response Design Criteria for Safety-Related Operator Actions (1994)."
Generic Letter 91-18 states: "The consideration of manual action in... areas also must include the ability and timing in getting to the area, training of personnel to accomplish the task, and occupational hazards to be incurred such as radiation, temperature, chemical, sound, or visibility hazards." ANSI-58.8 provides guidance on estimating response times for operator actions, and l
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l allows licensees to use time intervals derived from independent sources, provided they are based on task analyses or empirical data.
Following the licensee's letter of May 19,1997. requesting a change to its Technical Specifications, the NRC staff detemined ihe need for additional information. The licensee provided responses to the NRC staff's questions by letter dated August 25, 1997. The NRC staff evaluated the licensee's responses with regard to operator actions and times, environmental conditions, ingress / egress paths, procedural guidance, training, support personnel and equipment, information requirements, and plausible errors and recovery, as detailed below.
(1) Specific operator actions required:
The licensee stated that the following new manual oparttor actions would be required.
Prior to the UHS temperature exceeding 85 'F, the emergency overboard discharge valves (EA-HV 2356A and HV 23568, Service Water Loop A and B Yard Spray Valves) would need to be opened (per procedure HC.0P-AB.ZZ-0122(Q) rev.14, Step 4.12.2) and their associated power supply breakers (52-212131 and 52-222131) racked out (per procedure HC.0P-AB.ZZ-0122(Q) rev. 14, Step 4.12.4).
Closure of the SSWS/ SACS heat exchanger outlet valve would occur if the SACS temperature could not be maintained below 95 *F (per procedure HC.0P-AB.ZZ-0122(Q) rev. 14, Step 4.17). With the exception of racking out the power supply breakers, the actions involve manipulating two push-button controls and monitoring river water level and tenperature from the control room.
(2)
Potentially harsh or inhospitable environmental conditions expected:
The licensee stated that the local action of opening the breakers would occur during normal plant operation, therefore environmental condition; in the reactor building are not expected to be inhospitable or harsh.
(3)
Limitations or preferences of the ingress / egress paths taken by the operators to perform local functions:
The licensee noted that there are no limitations or preferred operator travel routes for the local manual actions needed to rack out the power supply breakers.
(4)
Procedural guidance for required actions:
The licensee submitted abnormal procedures, HC.0P-AB.ZZ-0122(Q) rev.14,
" Service Water System Malfunction" and HC.0P-AB.ZZ-0124(Q) rev. 9,
" Safety Auxiliaries Cooling System Malfunction.' These two procedures document the required operator actions.
. Also, an area of potential improvement was noted dur?ng the NRC staff's review of procedure HC.0P-AB.ZZ-0122(Q) rev. 14.
Caution 4.12 states that Steps 4.12 and (.13 should be executed concurrently. This can only be accomplished when river water temperature is equal to 85 'F.
The licensee may wish to consider clearly stating the meaning of these two steps.
(5)
Specific operator training necessary tc carry out actions including any operator qualifications required to carry out actions:
The licensee stated that all licensed operators were trained on the new actions. Training consisted of simulator scenarios with high UHS river water temperature conditions with a minimum shift crew complement. The testing evaluated operator response to elevated river water tem)erature conditions, including the crew responses to the SSWS and SACS a)r. Mal procedure guidance.
In all cases, the crews were able to complete the required actions in the time required.
(6) Any additional support personnel and equipment required by the operator to carry out actions:
The licensee stated that no additional support is needed to perform the new actions.
Equipment operators would be used to perform the local actions of racking out the breakers.
(7) Description of information required by the control room staff to determine such operator action is required, including qualified instrumentation (in accordance with Regulatory Guide 1.97,
" Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident,"
Revision 3, 1983) used to diagnose the situation and to verify that the required action has been successfully taken:
The licensee stated that the UHS average temperature, displayed on a strip chart recorder located in the control room, will be monitored to detemine when operator action is required.
In addition to the strip chart recorder, there are three alarms in the control room to indicate increasing UHS tecperature. One alarm is set at 80 *F, one at 82 'F, and one at 84 'F.
UHS average temperature can also be obtained from computer data. Operators would know that the required manual action was successful by the ability to maintain SACS temperature less than 95 *F.
SACS temperature is displayed in the control room both in analog and digital form.
(8) Ability to recover from plausible errors in performance of manual actions, and the expected time required to make such a recovery:
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[ The licensee's evaluation states that operator errors would require the plant be placed in a safe shutdo>:n condition.
For the new >ost-accident operator action, errors would not significar.tly challenge tie SACS system or its supported loads from performing thN r safety related functions.
The staff finds the previously discussed information consistent with ANSI /ANS 58.8 and Generic Letter 91-18 and, therefore, acceptable. Accordingly, the NRC Staff concludes that the licensee's responses related to the TS changes, which require taking credit for manual operator actions, are acceptable.
3.3 Technical Specifications On the basis of its calculations, the licensee has proposed changes to TS 3.7.1.3, " Ultimate Heat Sink." The first change would increase the minimum required UHS level from el. 76 feet (-13 feet mean sea level, USGS datum) to el. 80 feet (-9 feet mean sea level, USGS datum). This change to the TS is acceptable in that it increases the SSWS pump NPSH and is consistent with the licensee's calculation assumptions, as described in Section 3.1, herein. The licensee has also proposed decreasing the maximum normal UHS temperature from 88.6 'F to 85 'F.
This change is acceptable in that it is the temperature, calculated by the licensee, for the most limiting post-accident failure (E0B valve) in conjunction with the spectrum of component failures assaned in tne plant licensing basis.
Finally, the licensee has proposed a change to the Action Statement that specifies the remedial action that must be taken for continued plant operation when the UHS exceeds the maximum normal UHS temperature as specified in TS 3.7.1.3.
At the present time, the Action Statement is as follows:
With the river water temperature in excess of 88.6*F, but at or below 89.9'F, continued plant operation is permitted for 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> provided that both loops of SACS /SSWS are verified to be OPERABLE; otherwise, with the requirements of the above specification not satisfied:
[further remedial action]
The licensee has proposed that the above requirement be replaced with the following:
With the river water temperature in excess of 85.0'F, continued plant operation is permitted provided that all of the following conditions are satisfied:
ultimate heat sink temperature is below 87*F, both emergency overboard discharge valves are open and emergency discharge pathways are available, all SSWS pumps are OPERABLE, all SACS pumps are OPERABLE, all EDGs are OPERABLE and SACS loops have no cross-connected loads [unless they are automatically' isolated during a LOP and/or LOCA:; otherwise, with the requirements of the above specification not sat'sfied:
[same remedial action as the existing TS)
The above proposed TS is consistent with the system analysis addressed in Section 3.1, herein, and consistent with the analysis of assumptions regarding operator action addressed in Section 3.2, heretti. Accordingly, as these analyses have been found to be acceptable by the NRC staff, the proposed iS is also acceptable.
The licensee has proposed a change to the associated Surveillance Requirement, TS 4.7.1.3, to decrease the river water temperature at which increasing temperature surveillance is required, from 85 'F to 82 *F since the minimum UHS tem,)erature at which remedial action must be taken has been lowered from 88.6 'F to 85 *F.
Accordir.giy, the temperature at which increased UHS temperature surveillance must be undertaken should be likewise reduced to assure that UHS temperature limits are not violated.
Increased UHS temperature monit') ring at 82 *F is judged to be adequate to assure that system o)erability requirements at 85 'F will be observed. Accordingly, the proposed c1ange to TS 4.7.1.3 is acceptable.
The licensee has proposed that the requirements of TS 3.7.1.1, " Safety Auxiliaries Cooling System (SACS)," TS 3.7.1.2, " Station Service Water System (SSWS)," and TS 3.8.1.1, " Electrical Power Systems," be revised to reflect the revised TS 3.7.1.3.
Since continued operation above 85 *F is dependent upon the operability of SACS, SSWS and electrical power systems, the note "If continue operation is permitted by LCO [ Limiting Condition for Operation) 3.7.1.3,..." is inserted in TS 3.7.1.1, TS 3.7.1.2, and TS 3.8.1.1.
This insert is necessary to connect the requirements of TS 3.7.1.1 to the reference TS. Accordingly, the proposed changes to the TS are acceptable.
4.0 STATE CONSULTATION
In accordance with the Connission's regulations, the New Jersey State Official was notified of the )roposed issuance of the amendment.
In a letter dated September 7,1997, tie New Jersey State Official had the following comments:
In the proposed revisions, PSE&G removed a discussion in the Bases (3/4.7.1 Paragraph 2 Page B 3/4 7-1), on the function and actions relating to the heat removai capabilities of the SSWS and its safety-related sub-systems.
By contrast, NUREG 1433-Rev.1 (4/7/95) " Standard Technical Specifications, General Electric Plants, BWR/4" in Section B.3.7, covers the background, applicable safety analyses, and other issues for this plant cooling water system. The proposed Bases in LCR H97-02 do not adequately describe the need or the content of the technical specifications for ultimate heat sink and river water levels.
The NRC staff notes that, in accordance with 10 CFR Part 50, Section 50.36(a),
" Technical Specifications," the Bases are not a part of the Technical S>ecifications. While the Bases are useful in documenting the way in which t1e Technical Specifications satisfy the facility design requirements and
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safety analysis assumptions, licensees are free to prepare these Bases and change them without prior Commission approval.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to ins'allation or use of a facility component locMid within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC-staff-hti determined 4
thct the imendment involves no significant increase in the amounta, 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 the amendment involves no significant hazards consideration, and there has been no public comment on such finding (62 FR 33132 dated June 18,1997). Accordingly, the amendment meets the eligibility criteria-for categorical exclusion set forth in 10 CFR 51.22(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 the amendment.
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6.0 CONCLUSION
The Commission has concluded, based en the considerations discussed above, that:
(1) titare is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
D. H. Jaffe J. Bongarra M. Kotzalas Date: October 28, 1997 4
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