Text

Safety Evaluation Supporting Amend 141 to License NPF-6
	ML20126H438
Person / Time
Site:	Arkansas Nuclear
Issue date:	12/15/1992
From:	; Office of Nuclear Reactor Regulation
To:	;
Shared Package
ML20126H407	List: ML20126H403; ML20126H438;
References
	GL-84-15, NUDOCS 9301050197
	Download: ML20126H438 (10)
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SAFETY EVALUATION BY-THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 141TO FACILITY OPERATING LICENSE NO. NPF-6 ENTERGY OPERATIONS. INC..

q ARKANSAS NUCLEAR ONE. UNIT NO. 2 DOCKET NO. 50-368 1.0 JElflDDUCTION By letter dated October 9,1990, as supplemented by letters dated May 12, and September 28, 1992, Entergy Operations, Inc. (the licensee) submitted a request for changes to the Arkansas Nuclear _0ne, Unit No. 2 (ANO-2) Technical Specifications (TS). The requested changes would revise TS 3/4.8.1, "A.C.-

Sources," to achieve consistency with Generic Letter (GL) 84-15,-~" Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability." The changes are intended to reduce testing of the emergency diesel generators (EDGs) and improve their reliability.

Editorial changes are also made.-

The May 12, and September 28, 1992, letters provided clarifying information that did not change the initial proposed no significant hazards consideration determination.

2.0 EVALUATION Chance I Replace TS 3.8.1.1 Action a with the following:

a.

With one offsite A.C. circuit.of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY-of the-remaining-offsite A.C. circuit by performing Surveillance-Requirement 4.8.1.1.1.a within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter.

If either diesel generator 1 has not.been successfully tested within the past 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , demonstrate.its OPERABILITY _by.

performing Surveillance-Requirement'4'.8.1.1.2.a.4 separately for each diesel generator (unless it-is already' operating) within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .- Restore the offsite A.C.~ circuit to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and'in COLD. SHUTDOWN within_ the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

b.

- With one diesel _ generator of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of both the offsite A.C. circuits-by performing Surveillance Requirement t

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9301050197 921215 FDR -ADOCK 05000368 p

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4.8.1.1.1.a within I hour and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter.

If the diesel generator became inoperable due to any cause other than preplanned preventive maintenance or testing, demonstrate the OPERABILITY of the remaining OPERABLE diesel generator (unless it has been successfully tested in the last 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months or is already operating) by performing Surveillance Requirement 4.8.1.1.2.a.4 within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Restore the diesel generator to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

The above change splits the existing Action a into separate Actions a and b and negates required diesel generator testing for certain conditions (i.e.,

EDG inoperability due to preplanned maintenance or successful recent testing).

This meets the intent of the recommendations for reduced EDG testing contained in GL 84-15 and is consistent with the current staff position which is when an EDG is inoperable, the redundant EDG is-required to be tested primarily to ensure that common-mode failure mechanisms do not exist.

However, when an EDG is intentionally rendered inoperable for testing or maintenance, where the cause of the inoperability is readily known, there is no need for such additional testing.

Therefore this change is considered acceptable.

Chance 2 Replace current TS 3.8.1.1 Action b with the following:

c.

With one offsite A.C. circuit and one diesel generator of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the remaining offsite A.C. circuit by performing Surveillance Requirement 4.8.1.1.1.a within I hour and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter; and, if the diesel generator became inoperable due to any cause other than preplanned preventive maintenance or testing, demonstrate the OPERABILITY of the remaining OPERABLE diesel generator by performing Surveillance Requirement 4.8.1.1.2.a.4 within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months (unless it is already operating or has -

been tested within the last 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ).

Restore at least one of the inoperable sources to OPERABLE status within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months . Restore both offsite circuits and both diesel generators to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of the initiating event or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

This change contains several minor editorial revisions and negates required diesel generator testing for certain conditions. The change meets the intent of GL 84-15 and is consistent with the current-staff position as stated above in Change 1.

Therefore, this change is considered acceptable.

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[ hance 3 Replace current TS 3.8.1.1 Action c with the following:

d.

With two offsite A.C. circuits of the above required A.C. electrical power sources inoperable perform Surveillance Requirement 4.8.1.1.2.a.4 on the diesel generators within the next 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months (unless the diesel generators are already operating or have been successfully tested within the past 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months ).

Restore one of the inoperable offsite A.C. circuits to OPERABLE status within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

Restore both A.C. circuits within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of the initiating event or be-in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

The above change contains several minor editorial revisions and negates required diesel generator testing for certain conditions. This meets the intent of GL 84-15 and is consistent with the current staff position which is based on the requirement that EDG operability be demonstrated by a simple test every 31 days during normal operation.

Since the loss of two offsite sources degrades the overall plant electrical system significantly, it is desirable-to provide additional assurance of the availability of the remaining ac power sources.

Based on this, the staff has determined that it is prudent to.

demonstrate EDG operability within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months when two offsite sources are inoperable.

Therefore this change is considered acceptable.

Channe 4 Replace current TS 3.8.1.1 Action d with the following:

e.

With two diesel generators of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the two offsite A.C. circuits by performing Surveillance. Requirement 4.8.1.1.1.a within I hour and at least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months thereafter.

Rostore one of the inoperable diesel generators to OPERABLE status within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months . Restore both diesel generators within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months of the initiating event or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD' SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

This change contains several minor editorial revisions and is-acceptable.

Channe 5 At the end of the first line under Specification 4.8.1.1.2, add "(Note 1)."

Also add the following new footnote as the reference:

o; Note 1 All planned diesel generator starts for the purposes of these surveillance may be preceded by prelube procedures.

This change meets the intent of the recommendations for reduced cold fast starts contained in GL 84-15 and is consistent with the current staff position based on plant operating experience which has demonstrated that failure to prelube EDGs can eventually cause catastrophic EDG failures.

On this basis, engine prelube is encouraged as a means of improving EDG reliability.

i Occasional EDG starts without prelube (i.e., actual demand tests) can be tolerated only on a limited basis. 0)erating experience and test results have demonstrated that EDGs will start wit 11n their required time (usually 10 seconds) without prelube.

Engine prelude does not invalidate EDG test results but does enhance the overall EDG reliability.

Therefore this change is considered acceptable.

Chanae 6 In TS 4.8.1.1.2.a.4 delete " ambient" and substitute "from a standby condition" following " starts." Also add "(Note 2)" at the end of this specification.

Add the following new footnote as the reference:

Note 2 This diesel generator start from a standby condition in s 15 sec shall be accomplished at least once every 184 days. All other diesel generator starts for this surveillance may be in accordance with vendor recommendations.

This change meets the intent of the recommendations for reduced cold fast starts contained in GL 84-15 and is consistent with the current staff position intended to reduce confusion associated with the term " ambient." Some licensees have disabled the EDG keep-warm system prior to conducting EDG surveillance tests because they considered " ambient" to be room or outside air temperature.

This practice resulted in an excessive number of " cold-start" tests.

The term " standby" properly reflects the intended conditions _ for these tests and ensures that the tests will be conducted from a prewarmed condition which enhances overall EDG reliability. Therefore this change is considered acceptable.

Chance 7 In TS 4.8.1.1.2.a.5 delete "2850 Kw in s 60 sh onds" and substitute "an indicated 2600 to 2850 Kw."

Add "(Notes 3 & 4)" at the end of this specification. Also add the following new footnotes as the--references:

Note 3 Diesel generator loading may be accomplished in accordance with vender recommendations such as gradual loading.

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'. ktLA Homentary transients outside this load band due to changing loads will not invalidate the test.

Load ranges are allowed to preclude overloading the diesel pnerators.

This change meets the intent of the recommendations for reduced cold fast starts contained in GL 84 15 and is consistent with the current staff position based on the following.

Th original specification identified the EDG loading condition for testing as

' equal to or greater than 2350 kW. To satisfy this condition, operators would often run the EDG At t much greater load value which led to overload situations.

Sm.n practices caused accelerated engine wear and reduced EDG reliabilitys By using a load range for the required test condition, the test objectives will be satisfied without overloading the EDG.

Further, operating an EDG at 90% of its rated load will provide an adequate demonstration of the EDG's capability to operate at 100% load. The specified load range envelopes 90% to 100% of its rated load and is considered acceptable.

The change also specifies a rate of EDG loading in accordance with the EDG manufacturer's recommendations. The intent of the fast loading originally required in this specification (i.e., zero to full load in less than or equal to 60 seconds) was to roughly simulate the sequencing of loads onto the EDG during an actual emergency situation which generally takes in the neighborhood of about 60 seconds to complete. The fast loading requirement however meant that an operator had to quickly ramp up the load on the EDG in less than 60 seconds using the EDG governor speed adjust rheostat while avoiding overloading on the machine.

Because of the difficulty some operators had in load sequencing tests required by technical managing this and because 1) intervals also somewhat simulate the same thing, specifications at 18-month

2) the rapid loading although only required every six months could be viewed as detrimental.to EDG reliability, and 3) the rapid loading test did not necessarily challenge all the EDG auxiliary and control systems in the same manner as an actual load sequencing would, the staff has concurred with deletion of the fast loading requirement when requested by licensees.

Therefore this change is considered acceptable.

The note allowing momentary transients outside the load band is appropriate because of the dynamic nature of the grid to which the EDG is paralleled for loading.

Grid changes may effect EDG loading to the extent that the load would be outside the allowed band. This does not represe'.it a malfunction of the EDG, Adequate time is also allowed for the operator to adjust the load to within the required load range.

Chanae 8 In TS 4.8.1.1.2.c.5.b delete " ambient" aid substitute "a standby" in the first line. Add: "undervoltage" before " auto-start" in the second line, l

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.--c This change is editorial in nature and adds clarification to the Technical Specification. The change from " ambient" to " standby" is acceptable as discussed in Change 6 previously.

Chance 9 In TS 4.8.1.1.2.c.6 delete "an ESF" and substitute "a Safety Injection Actuation Signal (SIAS)" in the first line.

This change is editorial in nature and clarifies the

's, and is, therefore, considered acceptable.

Chanae 10 Move 1S 4.8.1.1.2.c.8.c and renumber as TS 4.8.1.1.2.c.7.

This change is editorial in nature and is, therefore, acceptable.

Chance 11 In TS 4.8.1.1.2.c.8 delete "an ESF" and substitute "SIAS" in the first line, Also place an *:" at the end of the second line.

This change is editorial in nature and is therefore acceptable.

Chanae 12 In TS 4.8.1.1.2.c.8.b delete " ambient" and substitute "a standby" in the first line.

Also delete " load sequencer" and substitute " Time Delay Relays" in the fifth line.

This change is editorial in nature and adds clarification to the Technical Specification.

The change from " ambient" to " standby" is acceptable as discussed in Change 6 previously.

Chanae 13 In TS 4.8.1.1.2.c.9 delete "3135 Kw" and substitute "an indicated 3000 to 3200 Kw."

Also delete "2850 Kw" and substitute "an indicated 2600 to 2850 Kw (Notes 3 & 4)."

Add the following new footnotes as the references:-

Note 3 Diesel generator loading may be accomplished'in accordance with vender recommendations such 'as gradual loading.

Note 4 Momentary transients outside this load band due to changing loads will not invalidate the test. Load ranges are allowed to preclude overloading the diesel generators.

This change meets the intent of the recommendations for reduced cold-fast starts contained in GL 84-15 and is consistent with the current staff position based on the following.

The original specification identified the EDG loading condition for the first two hours of the test as 3135 kW which is 110% of continuous duty rating of the EDG. The new proposed band for loading is 3000 kW to 3200 kW which is 105% to 112% of the EDG's continuous duty rating which envelopes the original load value while allowing for some minor variations in the EDG loading due to grid changes during the test. The change from 2850 kW to 2600 to 2850 kW for the remaining 22 hours2.546296e-4 days 0.00611 hours 3.637566e-5 weeks 8.371e-6 months of the test is acceptable as discussed previously in Change 7.

The change also specifies a rate of EDG loading in accordance with the EDG manufacturer's recommendations. The acceptability for this change is as discussed previously in Change 7.

The acceptability for the note allowing momentary transients outside the load band is as discussed previously in Change 7.

Chanae 14 In the last line of TS 4.8.1.1.2.c.9 delete " repeat Specification 4.8.1.1.2.c.5" and substitute " perform Specification 4.8.1.1.2.c.5."

Although this change appears to be editorial in nature, it does contain a-subtlety.

TS 4.8.1.1.2.c.5 is intended to be a " cold" (normal standby condition) start test of the diesel generator performed once every 18 months.

It is also to be performed again as a " warm" start test following the 24-hour test.

If the word " perform" is substituted for " repeat," the licensee could claim that TS 4.8.1.1.2.c.5 needs to be performed only once to satisfy the 18-month surveillance requirements. This is not the staff's intent and therefore we find the change unacceptable. However, by letter dated September 28, 1992, the licensee has replaced the word " perform" with " repeat" and the change is now acceptable.

[hanae 15 At the end of TS 4.8.1.1.2.c.9 add "(Note 5)." - Also add the following new footnote as the reference:

Note 5 If this test is not satisfactorily completed, it is not necessary to repeat the preceding 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months test, instead, the diesel generator may be operated at 2600 to 2850 Kw until internal temperatures stabilize but not-less than 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , then perform test 4.8.1.1.2.c.5 within 5 minutes.

This change is consistent with the current staff position that the whole 24-hour test does not need to be repeated if just the loss-of-offsite-power test is failed; that is, just the loss-of-offsite-power test needs to be

o

...c repeated after the diesel generator has been operated for 2 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months at full load. Therefore, we find this change acceptable.

Chance 16 In TS A.8.1.1.2.c.12 delete " emergency loads" and substitute " auto-connected emergency (accident) loads" in the fifth line.

This change is editorial in nature, clarifies the TS, and is, therefore, considered acceptable.

Chanae 17 Delete existing Table 4.8-1 in its entirety and substitute the following:

TABLE 4,8-1 DIESEL GENERATOR TEST SCHEDULE Number of Failures In Number of Failures In Last 20 Valid Tests

Last 100 Valid Tests

Test Freouency s1 54 At least once per 31 days 22 15 At least once per 7 days

Criteria for determining number of failures and number of valid tests shall be in accordance with Regulatory Guide 1.108, where the last 20/100 tests are determined on a per diesel generator unit basis.

This change follows the guidance contained in GL 84-15 and is therefore acceptable provided that a "**" is added following "7 days" in the table and the following footnote is added as the reference:

- This test frequency shall be maintaiaed until seven consecutive failure free demands have been oorfsimed and the number of failures in the last 20 valid demands Fas been reduced to one or less.

By letter dated Septembor 28, 1992, the licensee incorporated the at,ove footnote with the' additional statement "...and the number of failures in the last 100 valid demands has been reduced to four or less." This change further clarifies the TS, follows the guidance contained in GL 84-15, and is f

acceptable.

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t Chanae 18 In the Bases 3/4.8 on page B 3/4 8-1 at the end of the second paragraph, add-the following:

ACTION requirement: are consistent with Generic Letter 84-15, " Proposed Staff Actions to improve and Maintain Diesel Generator Reliability."

At the end of the fourth paragraph, add the following:

and Generic Letter 84-15.

Load ranges provided in surveillances are allowed to avoid routine overloading of diesel generators.

Load in excess of these load ranges for special testing, momentary variation due to changing bus loads, or short term variations shall not invalidate surveillance tests.

For the purpose of surveillance testing, the term

" standby condition" is defined as the approximate temperature range of the jacket cooling water and engine lube oil sump normally maintained by the engine keep warm systems. An exception to this definition is the engine conditions that exist when performing the hot restart test following the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months EDG endurance run. When performing this test, the engine is near normal operating temperature when in a " standby condition".

Additionally, this definition includes the allowance to perform engine prelubrication prior to all planned test starts.

The Diesel Genr ator Test Schedule, Table 4.8-1, has been developed for the purpose of determining testing requirements based on the number of failures and valid tests using the example provided in Generic Letter 84-15 using a per diesel generator unit basis. The criteria of R.G. 1.108 Position C.2.e is used for criteria determination.-

This change is editorial in nature, reflects the current staff requirement for EDG testing, and is consistent eith the changes approved with this TS s

amendment. On this basis it is acceptable.

3.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Arkansas State official was notif_ied of the proposed issuance of the amendment.

The State official had no comments.

4.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The NRC 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 no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a pro-posed finding that the amendment involves no significant hazards

., 'o consideration, and there has been no public comment on such finding (55 FR 49450). 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.

5.0 [QNCLUSION The Commission has 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, (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 Contributor:

F. Burrows Date: December 15, 1992

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ML20126H438

Text

3.0 STATE CONSULTATION

4.0 ENVIRONMENTAL CONSIDERATION

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