ML20127A510
| ML20127A510 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/02/1983 |
| From: | Mattson R Office of Nuclear Reactor Regulation |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML082410334 | List: |
| References | |
| FOIA-85-243 NUDOCS 8303150716 | |
| Download: ML20127A510 (7) | |
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GR 2M MEMDRANDUM FOR: Darrell G. Eisenhut, Direct'or Division of Licensing FRDM:
Roger J. Mattson, Director Division of Systems Integration SUSJECT:
EVALUATION OF DIESEL GENERATOR TECHNICAL SPECIFICATIONS I
SURVEILLANCE REQUIREMENTS, STANDARD TECHNICAL SPECIFI-CATIONS SECTION 4.8.1.1.2.d.6
REFERENCES:
1.
Memo to R. J. Mattson from S. H. Hanauer,
Subject:
Request for Evaluation of Proposed Change to San Onofre Unit 2 Diesel Generator Technical Specifi-cation Requirements May 6,1982 2.
Memo to S. H. Hanauer from J. L. Crews,
Subject:
Clarification of Diesel Generator Technial Specifications Surveillance Requirements. San Onofre Nuclear Generatin'g Station, Unit 2 Docket No. 50-361, March 16,1982 References 1 and 2 address the Diesel Generator Technical Specifications Surveillance Requirements which are referenced in Standard Technical Specifications Section 4.8.1.1.2.d.6.
Power Systems Branch's (PSB) evaluation of this surveillance requirement is discu sed in Enclosure 1 and supersedes the evaluation provided in our letter of June 18, 1982.
Our previous evaluation provided the clarification of the phrase "in accordance with design requirements," in the plant and Standard Technical Specifications.
After further study of the Standard Technical Specifications paragraph 4.8.1.1.2.d.6 requirements, as indicated in our memo of Jan. 14, 1983, we have concluded that this surveillance requirement is in excess of the scope of GDC 17. We find that there is no regulatory basis for this surveillance test requirement. The Standard Technical Specification contains other surveillance testing requirements that demonstrate the capability of the onsite power systen to perform its required functions in accordance witn'GD;
- 17. This surveillance requirement assumes a diesel generator failure (single failure) with loss of offsite power, and then reinstatement of the failed diesel generator with subsequent reloading of diesel via the load. sequencer.
In accordance with CDC 17, reouncant diesel generators are provided to reet the single fatiure crite-ton with loss of cffsite powa-
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Darrell G. Eisenhut g,g g We are providing information concerning items 2, a through g, per Office Letter No. 38 in Enclosure 2 for making changes to Generic Standard Technical Specifications.
For further infomation on this subject, contact Paul Gill on x27693.
Originsisigned bf1 floger J.Mattson Roger J. Mattson. Director Division of Systems Integration
Enclosure:
As stated cc:
L. Rubenstein M. Srinivasan J. E. Knight C. Thomas T. Novak D. Brinkman G. Lainas A. Ungaro E. Weinkam A. Gill' DISTRIB'JTION:
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ENCLOSURE 1 e-(.
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EVALUATION OF DIESEL GENERATOR TECHNICAL SPECIFICATIONS SURVEILLANCE REQUIREMENTS, STANDARD TECHNICAL SPECIFICATIONS SECTION 4.S.l.1.2.d.6 Backcround Paragraph 4.8.1.1.2.d.6 of the Standard Technical Specifications specifies a surveillance requirement that at least once every 18 months, during shutdown, cach diesel generator be demonstrated operable by, " Verifying that on a simulated loss of the diesel generator (with offsite power not available) the loads are shed from the emergency buses and that subsequent loading of the diesel generator is in accordance with design requirements." Reference 2 describes the lack of consensus between the Region V NRC staff and the licensee (Southern California Edison Ccmpany) regarding the interpretation of this surveillance requirement. Specifically, the specifications for shedding load and subsequent loading of the diesel generator in accordance with design requirements are not sufficiently understandable. Reference 1 requests an evaluation of this surveillance requirement and a generic change to the Standard Technical Specifications if necessary.
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the NRC staff for use in The surveillance requirement was developed by/ with regard to interaction evaluation of operating nuclear power plant 1 of the.offsite and onsite emergency power systems. This surveillance requirementig/requiredbyposition3"OnsitePowerSourceTesting" contained in reference _ which requires that the technical specifications include a.
test requirement to demonstrate the full operability and independence of the onsite power sources at least once per 18 months during shutdown. The technical specification for OR shall include a requirement for test, " simulating interruption and subsequent reconnection of onsite power sources to their respective buses," acccrding to the staff position.
Analysis and Evaluation The design requirement for onsite power sources (diesel generators) are described in NRC Regulatory Guide 1.9, " Selection. Design and Qualification of Diesel Generator Units Used as Standby (Onsite) Electric Power Systems at l
Nuclear Power Plants," to meet the General Design Criteria 17. " Electric Power System," of Appendix A, General Design Criteria for Nuclear Power Plants, to 10 CFR Part 50, " Domestic Licensing of Production and Utilization l
Facilities." This regulatory guide provides the essential design criteria for the selection of the diesel generator units used as standby electric power systems at nuclear power plarc;s.
1/ nclosure to Generic Letter -dated June 2,1977, Re: Millstone Nuclear E
Power Station Units Nos.1 and 2; " Safety Evaluation and Statement of Staff Positions Relative to the Emergency Power Systems for Operating Reactors" L
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. After the diesel generator units are selected, preoperational testing is perfomed to verify that the selected diesels conform to the design criteria specified in their selection. During preoperationP testing the selected diesel generator unit is required to demonstrate its capability to pickup design loads within a specified time period, and within specified voltage and frequency limits. This is a built-in characteristic of the selected diesel generator unit and with proper periodic service and maintenance its capability to perfom per design remains unchanged for its expected service life. Therefore, once these parameters are verified, these tests need not be duplicated periodically to ensure proper diesel generator performance.
Regulatory Guide 1.108, " Periodic Testing of Diesel Generator Units as Onsite Electric Power. Systems at Nuclear Power Plants," Section 2, item a.2 requires per. iodic testing at least every 18 months and it states, " Demonstrate proper operation for design-accident-loading-sequence to design-load requirements and verify that voltage and frequency are maintained within required limits."
To verify diesel generator performance and its ability to sequence loads within specified voltage and frequency limits during its service life, the necessary tests are to load the diesel generator in accordance with the loading sequence established in the FSAR, and once all loads have been sequenced on, it is sufficient to verify that the voltage and frequency are within limits. Any excess voltage and frequency dips during loading will result in diesel generator loading failures. Standard Technical Specifications include a battery of surveillance requirements to verify the generator's performance over its service life.
However, Standard Technical Specification paragraph 4.8.1.1.2.d.6 surveillanc'e requirements include surveillance testing features, that can be stated as:
(1) On simulated loss of diesel generator (with offsite power not available) the loads are shed.
(2) The failed diesel generator is reconnected to the emergency bus.
(3)
Loads are sequenced onto the bus through the load sequencer in accordance with the design requirements.
These requirements go beyond the single failure criterion, since it deals with operation of the diesel generator after a single failure has securred.
Standard Technical Specifications embody sufficient surveillance testing requirements to demonstrate the full functional operability and independence of the diesel generator units without these requirements.
Scecifically, to verify interaction of onsite power sources Mth loss of offsite power) with load shed feature, the following tests are specified in the Standard Technical Specification.
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. a) Verifying that on loss of offsite power the emergency buses have been deenergized and that the loads have been shed from the emergency bu.;es.
b) Verifying that on loss of offsite power the diesel generators start from ambient condition on the autostart signal, the emergency buses are energized with permanently connected loads, the autoconnected emergency loads are energized through the load sequencer, and the system operates for five minutes while the generators are loaded with the
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emergency loads.
Testing performed to satisfy the above surveillance requirements will demonstrate the capability of the onsite power system to meet its required functions to conform to GDC 17 and NRC regulatory guides requirements. Standard Technical Specification paragraph 4.8.1.1.2.d.6 surveillance requirement assumes a diesel generator failure (single failure) with loss of offsite power and then reinstatement of the failed diesel generator. However for single failure assumption (i.e. failed diesel generator) with loss of offsite power, redundant diesel generators are provided for onsite power sy:,tems to meet the GDC 17 requirements. Therefore, we conclude that there is no regulatory, hence design basis requirement to simulate a diesel generator failure (with loss of offsite power), to shed loads and subsequent reconnection of the failed diesel unit to the respective emergency bus.
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o EVALUATION OF PROPOSED CHANGE TO STANDARD DIESEL GENERATOR TECHNICAL SPECIFICATION SURVEILLANCE REQUIREMENTS Following is the additional information in support of the generic change in the Standard Technical Specification concerning the above reference in conformance with Office Letter No. 38.
Item 2:
(Office Letter No. 38) a.
Specification Language The requirements of paragraph 4.8.1.1.2.d.6 is deleted, b.
Bases Language The requirements of paragraph 4.8.1.1.2.d.6 of Standard Technical Specification are in excess of the scope of GDC 17. Therefore, there is no regulatory basis for this surveillance requirement.
c.
Supporting Rationale See Enclosure 1.
d.
Risk Reduction Assessment There is no change in risk due to the deletion of this surveillance requirement because of other surveillance test requirements, in the Standard Technical Specifications, which address and verify the diesel generator reliability and its ability to accept and reject loads to the stipulated design criteria.
The surveillance requirements necessary to verify operation in accordance with GDC 17 are all covered in the existing surveillance requirements of the Standard Technical Specifications.
e.
Value-Impact Analysis The proposed ch'ange imposes no increased or additional cost to the licensee (utility), since it deletes an unnecessary surveillance requirement.
It is anticipated that there will be less impact on the licensee because the surveillance criteria, as proposed under the generic change is not needed.
Also, there is no increased risk with the proposed change, f.
Proposed ImpTementation We recomend that this change be implemented as soon as possible for Operating Reactors (OR) that use standard technical specification and near-term Operating Licensee (OL) and Construction Permit (CP) plants.
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Category Desionation
- The category designation for this proposed change is 2 per Office Letter 38 Part II.
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Charl es E. '.: e'. ius, Director Division of : of e:t and Resident Drograms Region III FRO. :
Darrell G. E1:enhut, Director Division of Licensing Office of i;uclear Reactor Regulation SUEJECT:
fiRR POSITIC*i CN WHEft 'AN ACTION STATEMENT IS ENTERED AS A CONSEQUENCE OF FAILURE TO PEP. FORM SURVEILLANCE TESTS s
REFERENCE:
Memo from C.E. Norelius to D.G Eisenhut, dated January 31, 1983, subject: " Request for Technical Assistance - NRR Fosition on When 'an Action State-ment is Entered as a Consequence of Failure to Perfom Sur.veillance Tests".
The referenced memorandum requests NRR's position on when an Action Statement is entered as a consequence of failure to perform required surveillance tests. '
-*t is our position that Action Statements are entered when items required operable by Liciting Condition for Operations are known to be inoperable.
Items may be determined inocerable (1) during use, (2) during' a surveill-ance test, or (3) in accordance with Standard Techn'ical Specification 4.0.3 which provides that items are inoperable when Surveillance Require-cents are not performed within the specified time intervals (after applying the allowable tolerance).
Therefore, we agree with your position that Action Statements are entered when the Surveillance Requirements should have been perfomed rather than at the time it is discovered that tests were not performed.
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_~ S M'7 M,isenhut, Director 3ielMD Darrell G, t Division of Licensing Office of Nuclear Reactor Regulation Oc:
Director, Division of Prefect and Resident Programs Region I Region II Region III Regior IV Re;ior. V I
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Charles E. Norelius, Director Division of Project and Resident Programs Region III FROM:
Darrell G. Eisenhut, Director Division of Licensing Office of Nuclear Reactor Regulation
SUBJECT:
NRR POSITION ON SHUTDOWN TIliE ALLOWANCES WHEN AN LCO IS NOT MET
REFERENCE:
Memo from C. E. Norelius to D. G. Eisenhut dated February 9,1983, subject:. "Requ'est for Technical As'sistance - NRR Posi. tion on Shutdown Time Allowances When an LCO Is Not Met" The referenced memorandum requests NRR's position on licensees reducing plant operational modes prior to the expiration of the allowable out-of-ser~vice tim:s specified in technical specification Action Statements and then being permitted to utilize the unused portion of the higher mode allowable out-of-service time to extend the allowable time in a lower operational mode.
It is our position that it is acceptable for a licensee to initiate and com-plete a reduction in operational modes in a shorter time interval than required by the allowable out-of-service time specified in an Action Statement and then to add the unused portion of this allowable out-of-service time to that pro-vided for operation in a lower operational mode. Furthermore, it is our position that a stated allowable out-of-service time (frequently 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or 7 days) should be applicable regardless of the operational mode in which the inoperability is discovered. However, the times provided for achieving a r: duction in operational modes (e.g., generally 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> from Modes 1 or 2 to Mode 3, and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> from Mode 3 to Mode 4) should not be applicable if the inoperability is discovered in a lower operation mode.
The-following examples are provided to clarify our casitions:
Examcle 1 B&W STS 3.6.2.1 requires two independent containment spray systems OPERABLE
-in MCDES 1, 2, 3 and 4.
The Action Statement for this LC0 states:
"With one containment spray system inoperable, restore the inoperable spray system to OPERAELE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY witnin tne
- r. ext f hours; restere the inoperable spray syster to OPERABLE status within tne next 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or be in COLD SHUTDOWN witnin the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />".
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MEMORANDUM 40R:
Charles E. Norelius, Director Division of Project and Resident Programs FROM:
Darrell G. Eisenhut, Director Division of Licensing
SUBJECT:
NRR POSITION ON COMPONENT OPERABILITY WHEN A DIESEL GENERATOR IS INOPERABLE
REFERENCE:
Memo from C. E. Norelius to D. G. Eisenhut, dated February 16, 1983;
Subject:
" Request for Technical Assistance - Technical Specification Interpretation".
Your memorandum to me dated February'16,1983 (see reference) requested an interpretation by NRR on the subject of operability.
The requested inter-pretation was whether the loss of emerger.cy power to a system would render" that system inoperable for the purpose of satisfying another system LCO.
.Your memorandum included a specific example dealing with the core spray system and the high pressure coolant injection system at the Duane Arnold facility..
It is.our position that, in general, a system may be considered operable for the ' purpose of satisfying its own LCO and that of another system if only its emergency power supply is inoperable. This position assumes ttLat all the. provisions of Technical Specification 3.0.5 in. Enclosure 1 of my April 10, 1980 letter to All Power Reactor Licensees are also satisfied, i.e., a system may be considered operable for the purpose
_of satisfying its applicable LCO when its emergency power source is' inoperable provided the system's corresponding normal power source is operable, and its redundant train is also operable. These provisions have been incorporated into the Duane Arnold Technical Specifications as a clarification to the definition of Limiting Conditions for Operation.
'a'e realize that this position may result in a plant not being capable of fully satisfying the single failure criterion while operating in the degraded mode.
However, we consider such operation to be acceptable since it would be of limited duration and the probability of an accident occurring with a concurrent f ailure of the remaining operable-system is camotem
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'r. ycur memoranca.. you specifically askec:
' 1:n tne Core 5; ray Sys e.
cegraced by loss cf its energency poser source, is the Ccre 5; ray Syster to oe consicerec cperaole :: meet tne Higr. Pressure Coclar.: Injection System LC0?" Duane Arnoic Tecnnical Specification 3.5.D.2 is applicaole to this, example; it permits reactor operation to continue for up to seven, days providing that during such seven cays all active components of the ADS subsystem, the RCIC system, and LPCI subsystem and both core spray' subsystems are operable.
In accordance with our position, both core spray subsystems would be considered operable.
It should be noted, however, that our position is not intended to supersede the provisions of any technical specification which specifically requires the operability of diesel generators. For example, Duane Arnold Technical Specification 3.5.A.2 permits reactor operation to continue for up to seven days with one core spray subsystem inoperable provided the other core spray subsystem, the active components of the LPCI subsystem and the diesel generators are operable. Therefore, if one core spray subsystem and one diesel generator were inoperable, our position would not be applicable and continued operation would not be acceptable since Technical Specification 3.5.A.2 specifically requires the diesel generators to be op era bl e.-
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. Eisenhut, director Division of Licensing M
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