Text

Safety Evaluation Supporting Amend 94 to License DPR-54
	ML20149L276
Person / Time
Site:	Rancho Seco
Issue date:	02/09/1988
From:	; Office of Nuclear Reactor Regulation
To:	;
Shared Package
ML20149L242	List: ML20149L239; ML20149L260; ML20149L276;
References
	NUDOCS 8802240171
	Download: ML20149L276 (20)
	v • d • e

n aro,

[e v

UNITED STATES o,,

3 NUCLEAR REGULATORY COMMISSION g

WASHING TO N, D. C. 20555 3-

p

/

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 94 TO FACILITY OPERATING LICENSE DPR-54 RANCHO SECO NUCLEAR GENERATING STATION, UNIl 1 DOCKET NO. 50-312 1.0 INTR 00VCT10N Following the March 28, 1979 accident at the Three Mile Island Nuclear Generating Station, the Nuclear Regulatory Comission required all utilities to expand emergency electrical power distribution to include additional plant systems.

In the case of Rancho Seco, the additional power demands exceeded the capacity of the two emergency diesel generators.

To meet the additional emergency load requirements, two additional diesel generators were added to the Rancho Seco emergency electrical power distri-buiton system.

By letters dated October 2, 1986 and April 1, 1987, the Rancho Seco licensee, the Sacramento Municipal Utility District (SMUD), submitted proposed Technical Specification (TS) changes to incorporate TS require-ments which address the addition of the two diesel generators and the associated electrical distribution changes.

Supplemental submittals were made on December 13, 1986, September 22, 1987, October 8 and 26, 1987, and November 17, 1987, which modified the initial submittals by revising the proposed TS to more closely conform to the Standard B&W TS's.

The supplemental submittals did not change the application as noticed in the Federal Register on April 22, 1987.

2.0 EVALUATION OF DIESEL ENGINE RELATED TS SECTIONS a.

Proposed Specification 3.7.1.E This section of the proposed TS requires that the following condi-tions must be met in order to bring the reactor critical:

(1)

Separate day tanks containing)a minumum volume of 65 percent of tank capacity (265 gallons of fuel for each of the existing diesel generators A and B and 50 percent of tank capacity (315 gallons) of fuel for each of the new TDI diesel generators A2 and B2.

(2) A separate fuel storage system containing a minumum usable volume of 37,000 gallons of fuel for each of the existing diesel generators A and B, and 42,000 gallons of fuel for each of the new TOI diesel generators A2 and B2.

(3) A separate fuel transfer pump for each diesel generator.

SBR A8Ei SS8"h2 P

. These conditions are an extension of the original requirements to include the new equipment for the TDI diesels, ano as such, do not alter the concept of the original requirements. This proposed TS change is also consistent with the Standard Technical Specifications (STS). Therefore, the staff finds this section of the proposed TS to be acceptable, b.

Proposed Specification 3.27, Nuclear Service Electrical Building (NSEB) Emergency HVAC There are two trains of emergency HVAC to provide cooling to the safety related electrical equipment housed in the NSEB. The limiting condition for eperation (LCO) imposed in this section of the proposed TS is 7 days for one HVAC train inoperable and 3.5 days for two HVAC trains inoperable.

If the HVAC train (or trains) is not restored to operable status by the end of the LCO, the plant must be in cold shutdown within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months .

In addition, the proposed TS requires that if the NSEB temperature exceeds 104 F, reduce the NSEB temperature to less than 104"F within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , or the plant must be in cold shut-down within the next 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The staff finds this section of the proposed TS acceptable since it provides assurance that the required safety related equipment will be maintained operable, c.

Proposed Specification 3.28 TDI Diesel Generator Control Room Essential Ventilation System Thereisoneessentialventilationsystem(EVS)whichconsistsof two trains for each diesel generator control room. The function of the EVS is to maintain the proper temperature in the TOI diesel generator control room to preclude failure of the diesel control systems. The LC0 in the proposed TS permits 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to restore the inoperable EVS train to service or be in hot shutdown within the next six hours and cold shutdown within the following 30 hcurs.

In the event both EVS trains become inoperable, a requirement is imposed to restore the operability of at least one EVS train within two hours or be in hot shutdown within the next six hours and cold shutdown within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months . The requirements imposed in this section of the proposed TS are consistent with the STS.

Therefore, the staff finds this section of the proposed TS acceptable.

d.

Proposed Specification 4.6.3.A Items A-1, A.-2 and A-3 of this Section of the proposed TS cover partial surveillance requirements for the emergency diesel generators 1

including verification of the fuel level in the day tank, verification of the fuel level in the fuel storage tank, and verification of the fuel transfer system. They are consistent with the STS and are, therefore, acceptable.

i

. e.

Proposed Specification 4.6.3.B This section of tne proposed TS covers surveillance requirements for diesel fuel oil stored on site.

The licensee has proposed to use the same fuel oil surveillance program which was previously accepted by the staff for a number of other plants. This program differs from the STS in several areas. However, the staff previously concluded that the surveillance program for these plants is acceptable because it provides a more realistic assessment of the condition of the fuel oil than the STS including provisions for reducing the potential for fuel oil degradation.

The primary deviation of the licensee proposed TS from the STS is the deletion of the requirement for testing of stored fuel oil parti-culate concentration in accordance with American Society for Testing Materials (ASTM) D2274-70 every 92 days.

In lieu of the above, the proposed TS requires testing of stored fuel oil for particulate concentrations every 31 days in accordance with ASTM D2276-78. The proposed test more closely confirms the actual condition of the fuel oil that will be pumped to the diesel generators in terms of particulate matter which could impair diesel generator operation or result in diesel generator unavailability because of the greater test frequency.

The current STS surveillance requirements (ASTM D2274-70) are oriented to predicting the tendency of fuel oil to oxidize and form particu-lates during long term storage rather than detennining the particulate concentration that may already exist. The staff finds that the more frequent testing for actual particulates in the stored fuel oil will provide better indication of fuel conditions as well as identifying the tendency for formation of particulates under site storage conditions. The proposed tests would, therefore, be more conservative in establishing the adequacy of stored fuel than the present STS guidelines. The other proposed deviations include (a) sulfur analysis to be performed in accordance with ASTM D1552 or ASTM D2262, (b) extending the time limit for obtaining ASTM 0975 test results on new fuel from 14 cays to 31 days and (c) deleting the requirement for l

testing of stored fuel oil in accordance with 0975 requirements on a 92 day basis.

ASTM 0975 requirements are such that testing new fuel oil for sulfur content may only be performed in accordance with ASTM D129.

Federal diesel specification VV-F-8000 and ASTM D396, Specification for Fuel Oil, however, allow the use of ASTM D1552 and ASTM D2262 tests for sulfur determination in No. 2 grade fuel oil. The staff recognizes both of the above fuel oil specifications and believes that obtaining test results by their use will be equivalent to results obtained by use of ASTM D129 and, therefore, concludes that the proposed alternate methods of determining sulfur are acceptable.

l

4 The current Technical Specification guidelines indicate that new fuel oil to be tested for conformance to the limits of the respective fuel oil properties listed in Table 1 of ASTM 0975, and the test 1

results are to be available within 14 days following fuel oil delivery. Under the licensee's proposed surveillance program, the fuel oil properties with regard to imediate diesel engine operability (flash point, viscosity or gravity, water, and sediment) are checked for conformance to ASTM D975 limits imediately prior to accepting i

the new fuel.

The remaining fuel oil properties may affect diesel generator performance only on a long term basis.

Thus, the staff finds that the licensee's proposal to extend the. time for obtaining test resuits for the remaining fuel oil properties from 14 days to l

31 days would not adversely affect diesel generator operability.

The proposed Technical Specifications delete the requirement for testing of stored fuel oil in accordance with ASTM 0975 requirements on a 92 day basis. The rationale for this deletion is that the fuel oil properties which can affect diesel generator performance (flash 5

point, cetane number, viscosity, cloud point) do not change during storage.

If these properties are within specification when the fuel i

oil is placed in storage, they will remain within specification unless other non-specification petroleum products are added to the storage i

tanks. The addition of non-specification petroleum products is f

precluded by-the licensee's proposed new fuel surveillance program i

as described above. Over prolonged periods stored fuel can oxidize and form particulates which, in significant enough concentrations, could impair diesel generator perfonnance.

Particulate concentrations will be monitored every 31 days as discussed previously.

Bacteria growth will be prevented by periodic removal of water from the i

storage tanks as described in the proposed TS.

Because the fuel oil properties will not change in storage, and fuel oil conditions which could affect diesel generator operation will be closely monitored (on a 31 day basis), the staff finds that further testing of stored i

fuel in accordance with ASTM D975 every 92 days will not provide measurable improvement for diesel generator reliability. Therefore, such testing can be deleted.

The proposed TS also include two additions to the fuel oil surveillance Technical Specifications. These include (a) testing new fuel for i

flash point before acceptance, and (b) testing for and draining water from the fuel oil storege tanks every 31 days. The flash point test provides an additional indication that new fuel oil is within specification limits, thereby reducing the possibility of adding "bad fuel" to the fuel oil already in storage.

The requirement j

to drain accumulated water from the storage tanks every 31 days will i

be of considerable value in reducing the possibility of bacteria contamination of the stored fuel, minimizing the formation of corrosion products on the bottom of the storage tank, and in i

l preventing water from contaminating the fuel oil transfer system and the diesel generator fuel systems.

Both of the above additions represent a more conservative approach to maintaining quality diesel

~

fuel and diesel generator reliability than current STS guidelines.

i i

i l

. Based on our rev1ew of the proposed changes to the Rancho Seco Te:hnical Specifications for the new diesel engines the staff concludes that they are in accordance with the guidelines of the Standard Technical Specifications or an acceptable alternative. The staff, therefore, finds the proposed TS changes acceptable, f.

Proposed Specification 4.6.3.B. Item 1 This specification contains additional diesel engine surveillance requirements which were developed by the TDI diesel manufacturer and the BEI Owners Group. These surveillances are part of the TDI diesel qualification program which has been reviewed and approved by the NRC staff. The TDI diesel qualification program is described in the Rancho Seco Restart SER, NUREG-1286.

g.

Proposed Specification 4.32, TDI Diesel Generator Control Room Essential Ventilation System This specification includes surveillance requirement for the Diesel Generator Control Room Essential Ventilation System. The surveillance requirements are censistant with required surveillances of similar plant systems and are acceptable to the staff.

3.0 EVALUATION OF ELECTRICAL DISTRIBUTION RELATED TS CHANGES a.

Proposed Specification 3.7.1.A Existing specification 3.7.1.B which stated "Two 220kV lines are in service" has been redesignated 3.7.1.A and now reads "At least two physically independent circuits between the offsite transmission network and the onsite Class 1 distribution system are in service" in order to make it clear that more than two 220kV lines may be in service. The staff finds that the change has the same intended meaning, is more conservative (because all circuit components between the switchyard and Class 1 distribution system are clearly included in the specifications), and is, therefore, acceptable.

Existing specification 3.7.1.1 (originally included in the proposed specifications as 3.7.1.C) has been combined with proposed speci-fication 3.7.1.A. The combining of specifications does not change the

)

intended meaning of existing specification 3.7.1.A but does provide clarification.

The staff, therefore, finds the proposed change acceptable.

b.

Proposed Specification 3.7.1.B In order to correct an error, existing specification 3.7.1.0 which stated "The switchyard voltage is 215kV or above" has been redesignated 3.7.1.B and the text has been revised as follows:

"The switchyard voltage is 219kV or above." A 216.5kV voltage at the switchyard is i

i

. equivalent to the undervoltage trip point on the 4.16kV Class 1 buses.

Switchyard voltage must be above 216.5kV in order to maintain voltage on the 4.16kV buses. The allowable switchyard voltage has, thus, been corrected from 215 to 219kV.

Based on the above, the staff finds the proposed change to be acceptable.

c.

Proposed Specification 3.7.1.C 4

Existing specification 3.7.1.A has been changed to include the two new 4.16kV nuclear service buses which were added as part of the new diesel generator installation and to specifically identify which nuclear service buses ars required to be operable. This updating extends the original requirement to include the new electrical equipment, but does not alter the concept of the original requirement for operability of the safety related nuclear service buses. The staff, therefore, finds the proposed change acceptable.

In addition, nuclear services switchgear and nuclear service load shedding systems have been deleted from existing specification 3.7.1.A.

These items are considered part of nuclear services buses and must, therefore, be operable for the buses to be operable. The staff agrees that this deletion provides clarification, does not change the intended meaning of the specification, and is acceptable.

d.

Proposed Specification 3.7.1.0 Existing specification 3.7.1.A has been updated to include the new l

480V load centers and notor control centers which were added as part j

of the new diesel generator installation and to specifically identify which 480V nuclear services buses are required to be operable. This i

updating extends the original requirement to include the new electrical j

equipment, but does not alter the concept of the existing requirement for operab'lity of the 480V nuclear service buses. Since there is no ef.h tive change to the operability requirement, the staff concludes that the proposed updating is acceptable.

i e.

Proposed Specification 3.7.1.F Existing specification 3.7.1.E has been redesignated 3.7.1.F and has been updated to include the four new 125V batteries which were added to support loads being added to the electrical distribution system.

This change extends the existing requirement to include the new batteries, but does not alter the concept of the original requirement i

regarding the status of nuclear service batteries. Since there is 3

no effective change to the original requirement, the staff concludes that the proposed change is acceptable.

k i

l j

a i

. f.

Proposed Specification 3.7.1.G Existing specifications 3.7.1.F and 3.7.1.G include the requirements that "Two out of three battery chargers are operable for 125 volt DC buses SOA, SOB, SOC, and S00" and that "One out of two battery chargers are operable for each 125 VDC bus SOA2 and S082." The existing specifications have been updated to include the new 125V battery chargers which were added as part of plant electrical system changes.

In addition, the existing specifications have been combined and updated to require that each 125V bus have its "normal" battery charger operable versus two out of three chargers operable. The staff, concludes that the proposed specification is more conservative than existing speci-fications and is, therefore, acceptable, g.

Proposed Specification 3.7.1.H Existing specification 3.7.1.H has been modified to reflect changes to the plant 120V vital bus configurations. The existing speci-fication allows one inverter to be out of service indefinitely.

The proposed specification requires all the listed inverters and static transfer switches to be operable. The staff concludes that the proposed specification is more conservative and is, therefore, acceptable.

Existing specification 3.7.1.K (requiring the interconnection between 480V switchgear 3A and 3A2 and 3B and 3B2 to be operable) has been proposed to be deleted.

Because buses 3A2 and 3B2 will be powered by the new TDI diesel generators, the licensee indicated that the interconnections are no longer required. The staff agrees and therefore finds the proposed deletion acceptable.

Similarly, the periodic surveillance requirement contained in existing specification 4.6.2.A.2 for the interconnection has been deleted in the proposed specification. The staff finds the proposed celetion acceptable.

4.0 EVALUATION OF ELECTRICAL SYSTEM PREREQUISITES FOR REACTOR CRITICALITY a.

Proposed Specification 3.7.2.A The existing specification 3.7.2.A allows indefinite operation with only one 220kV line in service while the proposed specification limits the time only one offsite circuit is in service to 3 days or i

less if other restrictions are not met. The staff finds that the proposed change is more conservative than existing specifications and is, therefore, acceptable.

i 1

In accordance with the intended purpose of Generic Letter 84-15 to

~

reduce unnecessary diesel generator starts, it is the staff's position that if the diesel generators have been tested in the past 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , a retest within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of loss of all but one offsite l

2 circuit (as was originally required by action b of proposed speci-fication 3.7.2.A.1) is unnecessary. This item was discussed with the licensee and as a result action b of proposed specification 3.7.2.A was revised to be consistent with the staff position and recomendations of Generic Letter 84-15. The staff, therefore, considers this item to be acceptably resolved.

l Existing specification 3.7.2.B allowed continued plant operation with one startup transformer inoperable provided the loads normally supplied by the transformer were supplied by a diesel generator, f

There was no time limit on how long operation in this mode could sequentij deleted)ginally proposed specification, (which were sub-continue.

The ori i

(

pennitted a time of 24 and 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months for how long startup transformers 1 & 2, respectively, could be inoperable before start of plant shutdown and a 205 hour0.00237 days 0.0569 hours 3.38955e-4 weeks 7.80025e-5 months time to reach cold shutdown.

The proposed change imposes a new, more conservative, inoperability limit for the startup transformers and eliminated the requirement of running a diesel generator unnecessarily in accordance with the intent of Generic Letter 84-15.

The staff, therefore, found the proposed change acceptable. Subsequently, the licensee proposed combining (and thus changing) originally proposed specification 3.7.2.F with proposed specification 3.7.2. A.

On the same basis presented above and because inconsistencies between specifications are eliminated, the staff finds the proposed combined specification i

acceptable.

b.

Proposed Specification 3.7.2.B i

1 Existing specification 3.7.2.C allowed one diesel generator to be inoperable for up to 30 days under certain conditions. The 30 day inoperability limit and these conditions (i.e., daily load test on the remaining diesel generator for the first 15 da operation at minimum load for the second 15 days) ys and continuous have been replaced in the proposed specification.

The proposed specification replaces the 30 day limit with a 3 day inoperability limit and includes the new condition that at least two offsite circuits and the remaining diesel generators be periodically verified operable. The staff concludes that the change from 30 day to 3 day inoperability limit and the added condition that the offsite circuit be operable and periodically verified is more conservative than existing specific-ations, and is, therefore, acceptable.

In addition, it was noted that the proposed specification did not

{

apply to diesel generator inoperability caused by preplanned prevent-ive maintenance or testing. Thus, the staff found (for inopera-bility due to maintenance and testing) that the existing specification 3.7.2.C has been changed from inoperability for up to 30 days under certain conditions to an indefinite inoperability limit' with no conditions.

l

> This item was discussed with the licensee and as a result proposed specification 3.7.2.B.2 was further revised to include diesel generator inoperability due to maintenance and testing under the 3 day limiting condition for operation. Based on this further revision, the staff considers this item to be acceptably resolved.

l Also, in regard to inoperability of one diesel generator, existing specification 3.7.2.C requires daily load testing of the remaining diesel generator.

The proposed specification replaces this load test with a start only test of the diesel generator. When electric power sources are in a degraded condition (as would be the case with one diesel generator inoperable), the staff does not consider it prudent to place the remaining operable electric power sources in a configuration (i.e., diesel generator connected to the offsite power j

source for load testing) which would make them vulnerable to connon mode failure. On this basis the staff finds the proposed specification for diesel generator start only test to be acceptable; however, the staff also recognizes that starting the diesel generator without loading may be inconsistent with the manufacturer reconnendation that any time a diesel generator is started it should be loaded.

The staff is, therefore, concerned that a start only test that is not followed by loading may be detrimental to the continued capability of the diesel generator to accept load.

Although operation of the Rancho Seco EMD diesel engines at low loads is not reconnended by the manufacturer for long durations, the licensee maintains that occasional short terin operation is not detrimental to the availability of emergency power. Heavy duty turbo charger mechanical gear drive assemblies have been installed to assure optimum availability after running the engines at no-load or light load for extended periods.

Past experience has shown that the EMD diesel engines have run for at least I hour with no-load or light load and then accepted a load of 1500 kW and run for 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months at that load.

Based on the above considerations, the staff concern as related to the EMD diesel engines, is acceptably resolved.

The design of the Rancho Seco TDI diesel engines is fundamentally different from the Rancho Seco EMD diesel engine.

Because of these differences, the TDI engines are suitable for prolonged operation in no load or light-load conditions. The TDI engine has successfully undergone a special no-load endurance test for 168 hours0.00194 days 0.0467 hours 2.777778e-4 weeks 6.3924e-5 months followed by application of a 57 percent step load.

Based on the above consider-ations, the staff concern, as related to the TDI diesel engines, is acceptably resolved.

Existing specification 3.7.2.C had been updated to include operability of at least two 220kV transmission lines during inoperability of one diesel generator.

In justification the licensee indicated that the surveillance requirement had been revised to more clearly define the operability of offsite sources to be consistent with the recommenda-tions of Generic Letter 84-15. The typical technical specification l

o i l contained in Appendix A of Generic Letter 84-15 defines offsite

]

sources to be two physically independent circuits between the offsite j

transmission network and the onsite Class 1E distribution system.

i The originally proposed specification' addresses only offsite sources between the transmission lines and the plant switchyard. The circuit from (and including) the switchyard to the Class 1E buses and their independence had not been addressed in the originally proposed i

i specification. The staff, thus, found that the originally proposed j

specification were not consistent with the recommendations of Generic i

1 Letter 84-15. The licensee, in response to this finding, further modified the proposed specification in order to be consistent with technical specifications contained in Appendix A to Generic Letter 4

84-15. Based on this further modification, the staff considers' this i

item to be acceptably resolved.

Proposed action b (contained in originally proposed specification i

3.7.2.B.2) required immediate shutdown if any two diesel generators t

become inoperable. This requirement was the same as existing specification 3.7.3.

Because there was no change between existing l

and proposed specification, the staff found the proposed rewording i

of the specification to be acceptable. However, it was also noted that action item b (of originally proposed specification 3.7.2.B.3) allows 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months if diesel generators GEA 2 and GEB 2 are inoperable.

t Similarly action item e of proposed specification 3.7.2.E.1 allows i

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months if diesel generators GEA and GEA 2 or GEB and GEB 2 are l

inoperable and action item a of proposed specification 3.7.2.F.2'

[

allows 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months if diesel generators GEA and GEB, GEA and GEB 2, or t

GEB and GEA 2 are Inoperable. The licensee in response to these j

inconsistencies, modified proposed specifications 3.7.2.B.2 and deleted originally proposed specification 3.7.2.B.3.

Based on these 1

modifications and deletion, the staff considers this item to be accept-ably resolved.

i l

Proposed action a (centained in originally proposed specification l

1 3.7.2.B.2) required innediate shutdown if any single diesel generator i

and all but one 220kV line became inoperable. This requirement was i

j found to be more conservative than existing specification and was, therefore, considered acceptable. However, it was noted that proposed specification 3.7.2.C and 3.7.2.B.2 were inconsistent in that proposed l

1 specification 3.7.2.C allows 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (versus innediate) before start of shutdown.

In response to this inconsistency, the licensee i

i removed the innediate shutdown requirement from action a of proposed l

l specification 3.7.2.B.2.

With removal of this requirement, the staff considers this inconsistency to be acceptably resolved.

l i

Action c of paoposed specification 3.7.2.B.2 establishes a 3 day t

limiting condition for operation for inoperability of any one diesel i

generator. As indicated above, plant operation with one diesel l

generator inoperable for 3 days was found acceptable, however, as 1

part of action item d of specification 3.7.2.E.1 and action item e of l

specification 3.7.2.E.2, it was noted that this 3 day limit on plant t

l 1

l

O e operation may be extended from 3 days to as much as 12 days when one considers successive diesel generator failures.

In response, the licensee revised proposed specification 3.7.2.E.1 and 3.7.2.E.2 to eliminate the possible extension of the 3 day limiting condition for operation.

Based on the revised specification, the staff considers this item to be acceptably resolved.

Action b of originally proposed specification 3.7.2.B.3 allowed diesel generators GEA 2 and GEB 2 to be inoperable for up to 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months while existing specification 3.7.3 requires innediate shutdown.

In response to this finding, the licensee deleted proposed specification 3.7.2.B.3.

With this deletion, the staff :ensidered this item to be acceptably resolved.

Action b of proposed specification 3.7.2.B.2 requires testing of the remaining diesel generators within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months when any one diesel generator becomes inoperable.

If the diesel generator that was inoperable is restored in less than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months (e.g., 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months ), it is not clear if the remaining diesel generators must still be tested within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

In response to this item, the licensee added a note to require completion of test regardless of when the inoperable diesel generator is restored to operable status. Based on the added note, the staff considers this item to be acceptably resolved.

Action b of the proposed specification would also require additional diesel generator testing (i.e., at least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ) following the initial test. The staff (in accordance with the intended objective of Generic Letter 84-15 to reduce unnecessary diesel generator tests) considers this proposed additional testing requirement to be unnecessarily excess 1ve.

In response to this staff concern, the licensee modified the specification to remove the testing at least once per 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months thereafter requirement. The staff, therefore, considers this item to be acceptably resolved, c.

Proposed Specification 3.7.2.C Existing specifications 3.7.2.A and 3.7.2.C allowed unrestricted plant operation if only one 220kV line was operable and 30 days of operation with conditions if only one diesel generator train was operable.

Proposed specification 3.7.2.C has been added to clearly require a 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months limiting condition for plant operation if only one offsite circuit and one diesel generator train are operable. The staff finds the 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months limiting condition provides clarification, is more conservative than existing specification, and is, therefore, j

acceptable.

Proposed specification 3.7.2.C requires that proposed specification 3.7.2.A be followed if the diesel generator train is restored to operable within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months and proposed specification 3.7.2.B be followed if the offsite ci?cuit is restored to service within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . When reverting to 3.7.2.A or 3.7.2.B it was not clear when i

1

4 8 the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months limiting condition for operation commenced.

In response, the licensee revised the specification to provide clarification.

Based on this clarification, the staff considers this it a to be acceptably resolved.

d.

proposed Specification 3.7.2.D I

For loss of all offsite circuits, existing specification 3.7.2.0 has been changed from unlimited plant operation (with the condition that one diesel generator be run continuously) to a 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months limit on plant operation (with the condition that all diesel generators are demon-strated to be capable of being started).

The staff finds that the proposed change reduces unnecessary operation of diesel generators in accordance with Generic Letter 84-15, imposes a more conservative limiting condition for plant operation, and is, therefore, acceptable.

e.

Proposed Specification 3.7.2.E The existing specification 3.7.3 requires immediate plant shutdown if both diesel generators become inoperable while proposed specification 3.7.2.E.2 pennits 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months before start of shutdown.

In justifying the 2-hour limit, the licensee used the bases presented in position 4 of Regulatory Guide 1.93.

Since the offsite power system will be the only source of ac power when two diesel generators are inoperable, the risk associated with continued operation for a very short time (2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months ) could be less than that associated with immediate shutdown (the ininediate shutdown could cause grid instability which could result in total loss of ac power). Two hours is judged, by the licensee, to be the time required to complete the initial problem confirmation and coordinate the onsite shutdown activities for orderly plant shutdown. Two hours allows the offsite power dispatchers to take expedited actions to lessen the severity of the loss of this source to the grid. Two hours and the associated actions avoids the potentici risks of an innediate shutdown yet severely limits the plant's exposure time to this degraded condition. Two hours also allows sufficient time to correct minor problems and avoid unnecessary plant shutdown.

Based on the above, the staff agrees with the licensee and therefore finds the 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months time limit for plant operation to be i

acceptable.

Existing specification 3.7.2.C allows one diesel generator (i.e., one train in the old design) to be inoperable for 30 days with certain conditions.

Proposed specification 3.7.2.E.1 allows 3 days with other conditions where diesel generator combinations GEA and GEA 2 or GEB and GEB 2 are inoperable.

Since these combinations are the same as one train being inoperable in the old design, the licensee has proposed changing the 30 day limiting condition for. operation to i

3 days. The staff finds the change more conservative than existing specification and is, therefore, acceptable.

t

f

. 4

~

Existing specification 3.7.2.8 (i.e., both start up transfonners must 4

be in service except that one may be removed under certain conditions) implies that inmediate shutdown is required when both startup transformers are inoperable. The originally proposed specifications allowed two hours before action was required to shutdown the reactor when two startup transfonners were out of service. The final proposed specification (combinedinproposedspecification3.7.2.0) allows 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months before action is required to shutdown the reactor when two offsite circuits are out of service.

In justification, the licensee indicated that the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months LCO is consistent with guidelines con-tained in standard technical specifications and Regulatory Guide 1.93.

Since the onsite system has not been degraded when both offsite circuits are out of service and since simultaneous loss of offsite power and a LOCA were postulated as a design basis, a brief interval (24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months ) of continued operation is justified when both offsite circuits are out of service. Based on the above considerations, the staff finds, the proposed 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months LC0 for two offsite circuits out of service, to be acceptable, f.

proposed Specification 3.7.2.F Existing specification 3.7.2.G has been modified to reflect changes to the electric system design and to more clearly define the nuclear services buses which must be operable. The existing specification allows one nuclear service bus to be non-operable for 24 hourt with one condition. The proposed specification also allows one nuclear service bus to be non-operable for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months but without the one condition. The condition, all equipment on the other set of nuclear services buses must be operable, was removed from the proposed specification when one bus is non-operable.

Based on discussions with the licensee, the staff concludes that the intended purpose of the removed condition is included in Section 1.3 of the existing specification such that the intended condition, although not explicitly stated in proposed specification 3.7.2.H (3.7.2.F), is still required to be met. The staff, therefore, finds the proposed specification acceptable.

Existing specification 3.7.2.G required start of plant shutdown imediately for inoperability of two nuclear services buses while proposed specifications would permit two hours before shutdown.

This item was distyssed with the licensee and as a result this I

proposed specification was deleted. With the deletion, the staff considers this item to be acceptably resolved.

J' Existing specification 3.7.2.E has been proposed to be deleted. The a

requirementscontainedinthisexistingspecification(i.e.,oper-ability of essential nuclear service electrical buses, switchgear, load shedding, and automatic diesel start systems) are included in proposed specifications 3.7.1.C. 3.7.1.D. 3.7.1.E and 3.7.2.

The staff dgrees that the requirements of existing specifications have been incorporated in these proposed specifications and therefore concludes that the proposed deletion is acceptable.

. g.

Proposed Specification 3.7.2.G Existing specification 3.7.2.F requires nuclear services batteries to be charged and in service except one nuclear services battery may be removed from service for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months before start of plant shutdown.

Similarly, the proposed specification allows 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months before start of shutdown for one nuclear services battery. Based on this similarity, the staff finds the proposed specification acceptable. However, the proposed specification also allows two nuclear services batteries to be inoperable for 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months before start of shutdown while innediate shutdown is required by existing specificatiuns.

In response to this concern, the licensee removed the 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months allowable time before start of shutdown from the proposed specifications. The staff, therefore, considers this concern to be acceptably resolved, h.

Proposed Specification 3.7.2.H Operability requirements for battery chargers have been added in proposed specification 3.7.2.H in order to provide clarification of existing requirements for their operability. Because a battery charger must be operable in order for a battery to be charged, it can be inferred that existing specification 3.7.2.F allows one battery charger to be inoperable for up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . Similarly, the proposed specification allows one battery charger to be inoperable for up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Based on this similarity, the staff finds the oroposed f

specification to be acceptable.

Proposed specification 3.7.2.H has also added a 48 hour5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months limiting condition for plant operation when the standby charger is aligned in place of its nonnal charger.

Existing specifications allow use of the standby charger without any limiting condition for plant operation. The staff finds the 48 hour5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months limit more conservative than existing requirements and is, therefore, acceptable.

When more than one battery charger is out of service, originally proposed specification 3.7.2.J.c included a one hour allowable time before start of shutdown while existing specification can be inter-i preted to require an inneciate shutdown.

In response to this concern, the licensee removed the one hour allowable time from the proposed specification. The staff, therefore, considers this item to be acceptably resolved.

i 1.

Proposed New Specification 3.7.2.1 1

With one inverter out of service, Limiting Conditions for Operation j

(LCO)containedinexistingspecificationsisgovernedbythe individual LCOs for the components powered by. the out o.f service inverter.

Proposed specification 3.7.2.I allows one inverter or i

static switch to be inoperable for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

The licensee in justi-fication of the proposed LCO, indicated that the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months LCO for the

inverter and static switch is consistent with the LCO for the batteries and battery chargers which provide power to the inverter. On this basis the staff finds the proposed 24 LC0 for inverters and switches acceptable.

Because existing specifications do not specifically address inoper-ability of more than one inverter, it has been inferred that imediate shutdown is required by existing specifications. Originally proposed specification 3.7.2.K.2 allowed one hour before start of plant shutdown when more than one inverter or static switch is inoperable.

In response to the above described difference, the licensee deleted proposed specification 3.7.2.K.2.

The staff, therefore, considers this item to be accoptably resolved.

4 j.

Proposed Specification 3.7.2.J Existing specification 3.7.2.H requires one electrical division to be operated on its diesel generator independent of offsite power and the i

other electrical division to be operated on of fsite power with its associated diesel generator on standby status. The proposed speci-fication eliminates the requirement to continuously run a diesel generator and replaces it with a requirement to start each diesel generator within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months . The staff finds that the proposed speci-fication reduces unnecessary operation of diesel generators in accordance with recomendations of Generic Letter 84-15 and is, therefore, acceptable.

5.0 EVALUATION OF MODIFICATION TO VOLTAGE SENSORS (ProposedSpecifications 3.7.3 and 3./.4) i In order to prevent automatic diesel generator start due to transient overvoltage conditions, the design was changed to remove overvoltage protection originally provided on 4.16kV buses. The acceptability of this design change is addressed separately in the staff's Rancho Seco Restart Safety Evaluation Report. In regard to Tables 3.7-1, 3.7-2, and 4.1-1 of the proposed specifications, the staff finds that they have been changed to reflect the new design and are, therefore, acceptable.

Also, the licensee changed the design for undervoltage protection by adding (in parallel with the existing inverse time relays) a definite time delay undervoltage trip relay. The new design uses the existing inverse time relay as the first level of undervoltage protection and uses the added definite time delay relay as the second level of undervoltage protection. The acceptability of this design change is addressed separately in the staff's Rancho Seco Restart Safety Evaluation Report. Tables 3.7-1, 3.7-2, and 4.1-1 of proposed specifications reflects the addition of the new relays and their setpoints and is, therefore, acceptable.

)

i

,,_m

. j 6.0 EVALUATION OF MISCELLANE0US DIESEL GENERATOR RELATED TS CHANGES a.

Proposed Specifications 3.1.1.7 and 4.5.2.2.C This proposed specification addresses operability of pressurizer heaters and their emergency electrical power supplies. Proposed specification 4.5.2.2.C includes pressurizer heater associated surveillances. The pressurizer heater requirements are addressed in existing specification 3.7.4 In addition to modifying TS fonnat, the proposed specification reduces the pennitted plant operating time with heaters out of service from 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The proposed specification identifies requirements more clearly and is more conservative than the existing specification. The staff finds that the proposed change is an improvement over the existing specification.

b.

Diesel Generator Building Fire Protection Specifications (Tables 3.14-1and3.14-4andSection3.14.3)

The proposed specifications include requirements for fire detection instrumentation, sprinkler systems, and fire hose stations associated with the diesel generator building.

The addition of the fire pro-tection features to the diesel generator building is necessary to satisfy commitments regarding the fire protection guidelines of BTP CMEB 9.5-1 and the criterion of Appendix R to 10 CFR 50. The changes proposed by the licensee are consistent with the current standard technical specifications. Based on this evaluation, the staff finds the additional fire protection TS acceptable, j

i 7.0 EVALVATION OF CHANGES TO TS SURVEILLANCE REQUIREMENTS 4.

Table 4.1-1, Item 57 Item 57 of Table 4.1-1 has been changed to delete the once per shift requirement to compare voltmeter readings because if voltmeters are out of the calibrated range or the voltmeter indicates other than actual voltage one of two things will happen:

(a) The undervoltage relays would operate and (b) Alarms would sound in the control room, The staff agrees that once per shift comparison of voltmeter readings i

is unnecessary when alarms are available to alert the operator of undervoltage conditions. The staff, therefore, finds the proposed change to be acceptable.

Item 57 of Table 4.1-1 has also been changed to clarify' that monthly testing only verifies operability of undervoltage relays and that the setpoint and time delay are not quantitatively measured monthly. The i

staff finds that the proposed specification has the same intended meaning as existing specifications and is, therefore, acceptable, i

O

b.

Proposed Specification 4.6.1 The proposed specification adds surveillance requirements to demon-strate the operability of offsite circuits required by proposed specificati c 3.7.1.A.

Because the proposed surveillance is an added require wnt, the staff finds that the change provides clarifi-cation, is more conservative, and is, therefore, acceptable. This change is also consistent with the guidelines of the standard technical specifications, c.

Proposed Specification 4.6.2 The proposed specification adds surveillance requirements to demon-strate the operability of the nuclear services 4160V and 480V buses required by proposed specification 3.7.1.C and 3.7.1.D.

Because the proposed surveillance is an added requirement, the staff finds that the change provides clarification, is more conservative, and is, therefore, acceptable. This change is also consistent with the l

guidelines of the Standard Technical Specifications.

I d.

ProposedSpecification4.6.3.A(Items 4,5,6and7)

Existing specification 4.6.1 has been changed to incorporate reconenendations from Generic Letter 84-15 and more clearly identifies the requirements for demonstrating the operability of the diesel generators.

The staff's evaluation of these changes is described below:

Reference to a footnote (Note 1) has been added to proposed specification 4.6.3.A 4 and 4.6.3.A.5.

This note provides clarification with regard to the frequency of "fast starts."

Specifically, the note states that a fast start of the diesel generators, for this surveillance, must be conducted once per 184 days.

(A fast start is starting from ambient conditions andreachingratedspeedandvoltagewithin10 seconds). All other starts may include slow starts and gradual loading in accordance with manufacturer's recommendations.

In addition, all planned engine starts may be preceeded by a prelube period in accordance with manufacturer's recommendations.

Use of slow starts and gradual loading of diesel generators is consistent with the staff's goal of reducing rear and stress on the engines as stated in Generic Letter 84-15.

Therefore, the use of slow starts and gradual loading as defined in Note 1 is acceptable. Similarly, prelubing a diesel engine prior to starting as referenced in note 1 is another method for further reducing stress and wear. The staff, therefore, finds the use of a prelube period, as proposed, to be acceptable'.

Reference to a footnote has been addeJ to proposed specification 4.6.3.A.5.

The footnote states that the surveillance (i.e.,

paralleling the diesel generator with the offsite system and loading it to a specified value) will not be perfonned when one

l diesel generator train or offsite circuit is not operable.

When electric power sources are in a degraded conoition (as 4

i would be the case with one diesel generator or one offsite circuit inoperable), the staff does not consider it prudent to place the remaining operable electric power source in a config-i uration (i.e., diesel generator connected to the offsite power source for load testing) which would make them vulnerable to i

coninon mode failure. On this basis the staff finds the proposed 1

addition of the footnote to be acceptable.

Proposed surveillance 4.6.3.A.5 also includes a load range for i

the diesel generators (2550 to 2750 kw for l4 & B, 3000 to 3300 kw for A2 and B2). The purpose of the load range is to avoid routine overloading of the diesel generators during surveillance in ordec to meet technical specification requirements. This is i

another way of reducing wear and stress on diesel generators, j

The staff finds the proposed load ranges meet the intended l

objective of Generic Letter 84-15 and are, therefore, acceptable.

I j

Tables 4.6-1 and 4.6-2 have been added as part of the proposed specifications. Both Table 4.6-1 and Table 4.5-2 are consistent with the staff positions detailed in Generic Letter 84-15 with regard to reducing wear and stress on diesel generators and for i

improving their reliability. The staff, therefore, concludes a

that inclusion of Tables 4.6-1 and 4.6-2 in the proposed specifications is acceptable, j

in addition to the above, existing specification 4.6.3 has been changed

]

to more clearly identify the requirements for demonstrating operability i

of diesel generators and associated equipment. These changes include the addition of voltage, frequency, engine speed, and load requirements for i

demonstrating operability of the diesel generator and verification that the diesel generator can be aligned to its associated nuclear services bus.

The staff finds (except as noted below) that these changes are j

consistent with diesel generator operability requirements imposed on other g

recently assessed plants and are, therefore, acceptable.

1 The requirement that the diesel generators reach their required voltage, frequency, and speed levels in a specified time limit each 184 days was not clearly specified.

The licensee further modified the proposed i

specification to specifically require a 10 second time for fast start each 184 days. The staff, therefore considers this item to be acceptably resolved.

No specific time limit for loading each 184 days had been defined in the i

proposed specification.

In response, the licensee revised the proposed i

specifications to require loading within 90 seconds. The staff concludes j

that the 90 second time simulates diesel generator design loading under j

conditions as close to design as practical and is, therefore, acceptable, l

1 j

l I

1

)

. e.

Proposed Specification 4.6.3.C (Items 2, 3 and 4) i Existing specification 4.6.2 was relocated to Section 4.6.3 and has been changed by adding footnotes numbered 1 and 3 in order to incorporate the recommendations of Generic Letter 84-15. The staff's 1

evaluation of these changes is described below.

l Slow start and gradual load requirements contained in Note 1 of

{

originally proposed specification, are not applicable to loss of offsite power testing performed during refueling outages. Loss of offsite power testing should be conducted from ambient conditions and should duplicate, to the maximum extent possible, actual emergency conditions. Slow start and gradual loading are not acceptable.

l Therefore, reference to note 1 in this subsection is not acceptable.

1 In response to this item, the licensee removed reference to note 1 I

in proposed specification 4.6.3.C.3.

The staff, therefore, considers this item to be acceptably resolved.

Note 3 allows a prelube period prior to conducting diesel generator testing. The staff finds that the prelube period meets reconnendations of Generic letter 84-15 and is acceptable, f.

Proposed Specification 4.6.3.C.4 Existing specification 4.6.2.C was relocated to Section 4.6.3 and changed to clearly identify the requirements for load testing the diesel generators. This change included a 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months rated load test (i.e., 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months at load equal to the qualified short time rating and 22 hours2.546296e-4 days 0.00611 hours 3.637566e-5 weeks 8.371e-6 months at a load equal to the qualified continuous rating of the diesel generator.) The staff finds (except as noted below) that this change is consistent with diesel generator load testing requirements accepted on other recently licensed plants and is, therefore, accept-able.

The following items, considered by the staff to be part of diesel generator load testing, were not included as part of proposed periodic surveillance requirements for Rancho Seco. These items included:

a.

Capability to reject the largest connected load, b.

Capability to reject a load equivalent to its qualified continuous rating, c.

Capability to start when hot, and d.

Verification that auto-connected loads do not' exceed the qualified continuous load rating.

The licensee further modified the proposed specification to include the above listed items. The staff, therefore, considers this item to be resolved.

I J

4 d

' 9 Proposed Specification 4.6.3.0 A new surveillance requirement has been included as part of the proposed specification which verifies that all four diesel generators can start simultaneously once per 10 years or after any modifications which could affect interdependence. The staff finds the addition is more conservative than existing specification and is, therefore, acceptable.

8.0 CONTACT WITH STATE OFFICIAL The NRC staff has advised the Chief of the Radiological Health Branch, State Departnent of Health Services,. State of California, of the proposed determination of no significant rtzards consideration.

No consnents were received.

9.0 CONCLUSION

S a.

Environmental Consideration This amendment involves changes in the installation or use of a facility component located withn the restricted area as defined in 10 CFR Part 20 and changes to surveillance requirements. The staff has determined that the 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 not significant increase in individual or cumulative occupational radiation exposure. The Consnission has previously issued a proposed finding that this amendment involves no significant hazards considera-t tion and there has been no public consnent on such finding. Accordingly, this amendment meets the eli set forth in 10 CFR 51.22(c)gibility criteria for categorical exclusion (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.

b.

Conclusion i

We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in corpliance with the Cossnission's regulations, and (3) the issuance of the amendment will not be inimical to cosenon defense and security or to the health and safety of the public.

Principal Contributors: John Knox David Shum Dated: February 9, 1988

ML20149L276

Text

9.0 CONCLUSION

Navigation menu

Search