ML20206C565
| ML20206C565 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/31/1988 |
| From: | Myers T TOLEDO EDISON CO. |
| To: | |
| Shared Package | |
| ML20206C561 | List: |
| References | |
| 1588, NUDOCS 8811160324 | |
| Download: ML20206C565 (10) | |
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- Dock t No. 50-346 Lic n'a N3. NPF-3 S:ric1 No. 1588 Enclosure Page 1 APPLICATION FOR AliENDMENT TO FACILITY OPERATING LICENSE NO. NPF-3 L FOR DAVIS-BESSE NUCLEAR POVER STATION UNIT NO. 1 Attached are requested changes to the Davis-Besse Nuclear Pover Station, Unit No. 1 Facility Operating License No. NPF-3. Also included are the Safety Evaluation and Significant Hazards Consideration.
The proposed changes (submitted under cover letter Serial No. 1588) concern:
Technical Specification Surveillance Requirement 4.0.2.b; and Technical Specification Bases 4.0.2.
By }
T. J y s, Technical Services Director For D. C. Shelton Vice President, Nuclear Svorn and subscribed before me this 31st day of October , 1988.
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totary Public, State of Ohio LAURIE A. HINKLE Notary Public. State of Ohio My Commission E. spires May 15,1991 8811160324 89103g >
{Df< ADOCK 05000344 PDC
Dock 3t No.'50-346 .;
Lic:nsa No. NPF-3 Serial Ns. 1588 Enclosure Page 2 The following information is provided to support issuance of the requested changes to the Davis-Besse Nuclear Power Station, Unit No. 1 Operating License No. NPF-3, Appendix A Technical Specifiestions.
A. Time required to Implement: This change vill be implemented within 45 days after issuance of the amendment.
B. Reason for Changes (LAR No.88-004): Delete the applicability of Technical Specification Surveillance Requirement 4.0.2.b from 18-month, 18-month during shutdown and refueling interval Surveillance Requirements.
C. Safety Evaluation: See attached Safety Evaluation (Attachment No. 1)
D. Significant Hazards Consideration: See attached Significant Hazards Consideration (Attachment No. 2) i E. Technical Specification Change Pages: See attached marked up Technical Specification pages (Attachment No. 3)
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- Dockot N3. 50-346 Licenso N3. NPF-3 Scriel No. 1588 Attachment 1 Page 1 SAFETY EVALUATION TITLE Deletion of Technical Specification 4.0.2.b Applicability to 18-Honth Surveillance Requirements DESCRIPTIO_N The purpose of this safety evaluation is to provide justifiestion for deletion of Technical Specification 4.0.2.b applicability to 18-month surveillance requirements provided in Appendix A of the Davis-Besse Nuclear Power Station Technical Specifications. Deletion of Technical Specification 4.0.2.b applicability vill allow scheduling of 10-month surveillance requirements to correspond to scheduled refueling outages.
Technical Specification 4.0.2.a provides for a maximum allovable extension of surveillance requirement intervals by 25 percent. This provides a 4.5 month extension for 18-month surveillance requirements, giving a maximum single interval length of 22.5 months. Technical Specification 4.0.2.b requires that the total combined interval for any three consecutive tests not exceed 3.25 l' '
times the specified surveillance interval. This allows a maximum of 58.5 months for three consecutive test intervals. The safety function of Specification 4.0.2 is to provide a sufficiently restrictive tolerance value s on surveillance frequency to ensure adequate reliability of affected systems when deviations from nominal specified surveillance intervals occur.
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The current 18-month surveillance period in the Technical Specifications was intended to accommodate a 12-month fuel cycle at the time the original B&V Standard Technical Specifications (NUREG-0103) vere written. Adequate flexibility was provided for these 18-month surveillance requirements to be performed during scheduled refueling outages, if a 12-month fuel cycle was realized. Further, the provisions of Specification 4.0.2.b, as stated in the Basis Section of the Technical Specifications, allow additional margin necessary to provide operational flexibility because of scheduling and performance considerations. However, over the years, nuclear core designs I
have progressed from 12-month fuel cycles to longer operating cycle lengths to improve unit availability and fuel utilization. Vith longer operating cycles, t coupled with occasional long refueling and maintenance outages, scheduling of
- surveillance requirements at an 18-month interval required by Technical Specifications becomes increasingly difficult. Further, due to less than optimum plant capacity factors, the period between refueling outages may often exceed 18-months. As long as the interval is less than 22.5 months, Specifications 4.0.2.a can be complied with. However, the cumulative effect of operating periods greater than 18 months is that the 18-month rurveillance requirements are constrained by Technical Specification 4.0.2.b.
In the Technical Specifications, there are over 70 18-month interval Technical Specification surveillances that must be performed during shutdown in rfodes 4, 5 or 6. In addition, there are other 18-month surveillances that are performed in other modes. Recent reviews of the upcoming Cycle 6 indicate
Dockst No. 50-346 Liccn:2 Na. NPF-3 Serial No. 1588 Attachment 1 Page 2 that the 1.25 limit (i.e., 4.0.2.a limit) vill not be reached for any surveillance requirement, however, the 3.25 limit (i.e., 4.0.2.b limit) vill be reached for more than 23 surveillance requirements prior to the next scheduled refueling date of February 10, 1990, (tentative, based on a 76 percent average capacity factor for Cycle 6).
Therefore, to comply with Specification 4.0.2.b, a shutdown during the middle of the cycle vill be required to complete these tests. This is considered to be undesirable based on the following:
- Shutdovn of the plant imposes transient conditions on equipment potentially causing equipment failures due to thermal stresses and on/off cycling of rotating machinery.
- Performance of surveillances requiring access to containment increases the potential for personal exposure to radiation.
- The scheduling of a mid-cycle surveillance outage of sufficient duration to meet all the surveillance requirements vould place a significant and unvarranted drain on resources.
- The same type of surveillance outage could potentially also be required for subsequent operating cycles.
- The original intent of 18-month surveillance requirements var that they would be performed during refueling, and not that they muld force plant shutdown for test performance.
To avoid the problem that vill othervise exist during the sixth operating cycle and to prevent its recurrence during subsequent cycles, it is proposed that the Technical Specitications be revised to reflect that provisions of Specification 4.0.2.b are not applicable for those surveillances required to be performed at least once per 18 months, including those identified by the letter "R" as defined in Table 1.2 of the Technical Specifications. This vill eliminate, for operating cycles less than 22.5 months long, the need for a mid-cycle shutdown solely for the performance of 18-month surveillance tests.
DOCUMENTS AFFECTED Davis-Besse Nuclear Fover Station, Unit No. 1, Operating License, Appendix A, Technical Specifications.
EFFECTS ON SAFETY )
The limiting conditiens for operation (LCO) and other required surveillances to verify operability as defined in the Technical Specifications remain in effect and unchanged by the proposed amendment. The provisions of Specifications 4.0.2, as described in the bases section of Technical Specifications, provide allovable tolerances for performing surveillance activities beyond those specified in the nominal surveillance interval. The current criterion of 4.0.2 allows a 22.5 month interval (4.0.2.a) for as many
Dockst N . 50-346 Lic:nsa N). NPF-3 Serial No. 1588 Attachment 1 Page 3 as two intervals during a three-interval period (i.e., 22.5 + 22.5 + 13.5 -
58.5). However, the third interval period is constrained to a length no greater than 13.5 months if the two 22.5 nonth intervals are used, per the current criterion of 4.0.2.b.
Deletion of Specification 4.0.2.b vill not affect the intent of the safety function of 4.0.2. The safety function of Specification 4.0.2 vill be maintained since the 18-month surveillance interval vill still be adequately constrained by the maximum 25 percent interval extension criterion of Specification 4.0.2.a. The bases section for Specification 4.0.2 provides further details regarding the tolerance values and their purpose, as follows:
The tolerance values, taken either individually or consecutively over 3 test intervals, are sufficiently restrictive to ensure that the reliability associated with the surveillance activity is not significantly degraded beyond that obtained from the nominal specified interval.
Deletion of the 3.25 criterion of Specification 4.0.2.b vill permit all 18-month surveillance intervals to be a maximum of 22.5 months duration.
Allowing this proposed change to be applied to all 18-month surveillance intervals vill continue to maintain a sufficient level of protection, as stated in the bases section above. Further, the proposed amendment does not extend the fault exposure time for any affected component beyond the currently allowed 22.5 months, per Specification 4.0.2.a.
UNREVIEVED SAFETY OVESTION EVALUATION The proposed action vould not increase the probability of an accident previously evaluated because the system reliability and fault exposure time remain essentially the same, as assured by compliance with Technical Specification 4.0.2.a. Therefore, there is no increase in accident probability.
The proposed action vould not increase the consequences of an accident previously evaluated in the USAR because the system reliability and fault exposure time remain essentially the sam 2, as assured by compliance with Technical Specification 4.0.2.a. The equipment vill still function and the accident response vill be as assumed in the USAR.
The proposed action vould not increase the probability of a malfunction of equipment important to safety because the 18-month surveillance interval vill still be constrained to 22.5 months by Specification 4.0.2.a, which vill provide a sufficient level of protection. Allowing all 18-month surveillance intervals to be 22.5 months vould not incrense the probability of a malfunction of equipment important to safety. This vill ensure the equipment continues to perform as currently assumed in the USAR.
The proposed action vould not increase the cunsequences of a malfunction of equipment important to safety because the proposed change does not involve a modification to any of the equipment affected or a change in operation of existing system (s). Furthermore, it vill not prevent any system from functioning as assured in the USAR.
Dockat Na. 50-346 Liccnsa Na. NPP-3 Serial No. 1588 Attachment 1 Page 4 The proposed action vould not create a possibility for an accident of a different type than any evaluated previously in the USAR because this proposed amendment does not add or modify any existing equipment. The 18-month surveillance interval vill still be constrained by the maximum 25 percent interval extension criterion of Specification 4.0.2.a.
The proposed action vould not create a possibility for a malfunction of equipment of a different type than any evaluated previously in the USAR because this proposed amendment does not add or modify any existing equipment.
Additionally, per Technical Specification 4.0.2.a, a 22.5 month interval vill provide a sufficient level of protection. Therefore, no new malfunction of equipment vill occur. i The proposed action vould not reduce the overall margin of safety as defined [
in the basis for any Technical Specification because allowing the requirement for "any 3 consecutive intervals must not exceed 3.25 times the specified surveillance interval" to be not applicable to 18-month surveillances vill not affect equipment reliability beyond what is allowed by the requirements of Technical Specifications 4.0.2.a. Per Technical Specification 4.0.2.a a 22.5 month interval provides a sufficient level of protection. Since equipment I reliability as required by the bases in the Technical Specifications vill be maintained, the margin of safety vill also be maintained. '
CONCLUSION Based on the above, it is concluded that the proposed Technical Specification I change does not constitute an unreviewed safety question.
REFERENCES ,
l Davis-Besse Nuclear Pover Station, Unit No. 1, Operating License, Appendix A, !
Technical Specifications.
Davis-Besse Nuclear Power Station, Unit No. 1, Updated Safety Analysis Report, L Revision 7, July, 1988.
Dockot No. 50-346 Lic:nsa No. NPF-3 Serial No. 1588 Attachment 2 Page 1 SIGNIFICANT HAZARDS CONSIDERATION TITLE Deletion of Technical Specification 4.0.2.b Applicability to 18-Honth Surveillance Requirements DESCRIPTION The purpose of this significant hazards consideration is to review the justification for deletion of Technical Specification 4.0.2.b applicability to 18-month surveillance requirements provided in of the Davis-Besse Nuclear Power Station Technical Specifications. Deletion of Technical Specification 4.0.2.b applicability vill better provide for the scheduling of 18-month surveillance requirements during scheduled refueling outages.
Technical Specification 4.0.2.a provides for a maximum allovable extension of surveillance requirement intervals by 25 percent. This provides a 4.5 month extension for 18-month surveillance requirements, giving a maximum single interval length of 22.5 months. Technical Specification 4.0.2.b requires that the total combined interval for any three consecutive tests not exceed 3.25 times the specified surveillance interval. This allows a maximum of 58.5 months for three consecutive test intervals. The safety function of Specification 4.0.2 is to provide a sufficiently restrictive tolerance value on surveillance frequency to ensure adequate reliability of affected systems when deviations from nominal specified surveillance intervals occur.
The current 18-month surveillance period in the Technical Specifications was intended to accommodate a 12-month fuel cycle at the time the original B&V Standard Technical Specifications (NUREG-0103) vere written. Adequate flexibility was provided for these 18-month surveillance requirements to be performed during scheduled refueling outages, if a 12-month fuel cycle was realized. Further, the provisions of Specification 4.0.2.b, as stated in the Basis Section of the Technical Specifications, allow additional margin micessary to provide operational flexibility because of scheduling and performance considerations. However, over the years, nuclear core designs have progressed from 12-month fuel cycles to longer operating cycle lengths to improve unit availability and fuel utilization. Vith longer operating cycles, coupled with occasional long refueling and maintenance outages, scheduling of surveillance requirements at an 18-month interval required by Technical Specifications becomes increasingly difficult. Further, due to less than optimum plant capacity factors, the period between refueling outages may often exceed 18-months. As long as the interval is less than 22.5 months, Specifications 4.0.2.a can be complied with. However, the cumulative effect of operating periods greater than 18 months is that the 18-month surveillance requirements are constrained by Technical Specification 4.0.2.b.
In the Technical Specifications, there are over 70 18-month interval Technical Specification surveillances that must be performed during shutdown in Modes 4, 5 or 6. In addition, there are other 18-month surveillances that are
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- Dockot Ns. 50-346 Licensa No. NPF-3 Serial No. 1588 Attachment 2 Page 2 performed in other modes. For example, recent reviews of the sixth operating cycle indicate that the 1.25 limit (i.e., 4.0.2.a limit) vill not be reached for any surveillance requirement, however, the 3.25 limit (i.e., 4.0.2.b limit) is expected to Le ranched for more than 23 surveillance requirements prior to the next scheduled refueling date of February 10, 1990, (tentative, based on a 76 percent average capacity factor for Cycle 6).
Therefore, to comply with Specification 4.0.2.b, a shutdown during the middle of the cycle vould vill be required to complete these tests. This is considered to be undesirable based on the following:
- Shutdown ol' the plant imposes transient conditions on equipment potentially causing equipment failures due to thermal stresses and on/off cycling of rotating machinery.
- Performance of surveillances requiring access to containment increases the potential for personal exposure to radiation.
- The scheduling of a mid-cycle surveillance outage of sufficient duration to meet all the surveillance requirements vould place a significant and unvarranted drain on resources.
- The same type of surveillance outage could potentially also be required for subsequent operating cycles.
- The original intent of 18-month surveillance requirements vas that they vould be performed during refueling, and not that they vould force plant shutdown for test performance.
To avoid the problem that vill othervise exist during the sixth operating cycle and to prevent its recurrence during subsequent cycles, it is proposed that the Technical Specifications be revised to reflect that provisions of Specification 4.0.2.b are not applicable for those surveillances required to be performed at least once per 18 months, including those identified by the letter "R" as defined in Table 1.2 of the Technical Specifications. -This vill eliminate, for operating cycles less than 22.5 months long, the need for a mid-cycle shutdown solely for the perfotJance of 18-month surveillance tests.
DOCUMENTS AFFECTED Davis-Besse Nuclear Pover Station, Unit No. 1, Operating License, Appendix A, Technical Specifications.
EFFECTS ON SAFETY The limiting conditions for operation (LCO) and other required surveillances to verify operability as defined in the Technical Specifications remain in effect and unchanged by the proposed amendment. The provisions of Specifications 4.0.2, as described in the bases section of Technical Specifications, provide allovable tolerances for performing surveillance activities beyond those specified in the nominal surveillance interval. The current criterion of 4.0.2 allovs a 22.5 month interval (4.0.2.a) for as many
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- Dockot N2. 50-346 Lic:nsa No. NPF-3 Serial No. 1588 Attachment 2 Page 3 as two intervals during a three-interval period (i.e., 22.5 + 22.5 + 13.5 -
58.5). However, the third interval period is constrained to a length no greater than 13.5 months if the two 22.5 month intervals are used, per the current criterion of 4.0.2.b.
Deletion of Specification 4.0.2.b vill not affect the intent of the safety function of Specification 4.0.2. The safety function of Specification 4.0.2 vill be maintained since the 18-month surveillance interval vill still be adequately constrained by the maximum 25 percent interval extension criterion of Specification 4.0.2.a. The bases section for Specification 4.0.2 provides further details regarding the tolerance values and their purpose, as follows:
The tolerance values, taken either individually or consecutively over 3 test intervals, are sufficiently restrictive to ensure that the reliability associated with the surveillance activity is not significantly degraded beyond that obtained from the nominal specified interval.
Deletion of the 3.25 criterion of Specification 4.0.2.b vill permit all 18-month surveillance intervals to be a maximum of 22.5 months duration. !
Allowing this proposed change to be applied to all 18-month surveillance intervals vill continue to maintain a sufficient level of protection, as stated in the bases section above. Further, the proposed amendment does not
- extend the fault exposure time for any affected component beyond the currently allowed 22.5 months, per Specification 4.0.2.a. A revision to Basis 4.0.2 has been proposed which discusses the acceptability of the deletion of the 3.25 criterion to 18-month surveillance intervals.
SIGNIFICANT HAZARDS CONSIDERATION The Commission has provided standards in 10CFR50.92(c) for determining whether a significant hazards exists. A proposed amendment to an Operating License for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed changes voulds (1) Not involve a significant increase in the probability or consequences of an accident previously evaluatedt (2) Not create the possibility of a new or different j kind of accident from any accident previously evaluated; or (3) Not involve a significant reduction in a margin of safety. Toledo Edison has reviewed the proposed changes and determined that a significant hazards consideration does not exist because operation of the Davis-Besse Nuclear Power Station, Unit No. 1, in accordance with these changes vould:
Not involve a significant *acrease in the probability or consequences of an accident previously evaluated because surveillance intervals vill still be limited by Technical Specification 4.0.2.a. Technical Specificatton 4.0.2.a provides allovable tolerances for performing surveillance requirements beyond those specified in the normal surveillance interval. Deletion of the 3.25 criterion of Specification 4.0.2.b vill better provide for 18-month surveillances to be performed during refueling outages, as was intended, and eliminate the need for mid-cycle shutdovns solely for the performance of these surveillances. (10CFR50.92(c)(1)).
- Docket Ns. 50-346 #
Liesnsa No. NPF-3 Serial No. 1588 Attachment 2 -
Page 4 7
Not create the possibility of a new or different kind of accident from any l accident previously evaluated because the proposed change does not add or modify any system design nor does it involve a change in operation of any i plant system. Technical Specification 4.0.2.a provides allovable tolerances l 1
for performing surveillance requirements beyond those specified in the normal i surveillance interval. Deletion of the 3.25 criterion of Specification i 4.0.2.b vill better provide for 18-month surveillances to be performed during I 4
refueling outages, as was intended, and eliminate the need for mid-cycle shutdowns solely for the performance of these surveillances. ;
L i Not involve a significant reduction in the overall margin of safety because t surveillance intervals vill still be limited by Technical Specification ;
4 4.0.2.a. Technical Specification 4.0.2.a provides allovable tolerances for performing surveillance requirements beyond those specified in the normal l surveillance interval. Deletion of the 3.25 criterion of Specification 4.0.2.b vill better provide for 18-month surveillances to be performed during refueling outages, as was intended, and eliminate the need for mid-cycle shutdowns solely for the performance of these surveillances. l J (10CFR50.92(c)(3)). l i
CONCLUSION ,
i i j On the basis of the above, Toledo Edison has determined that the amendment !
j request does not involve a significant hazards consideration. f i
REFERENCES j l
1 Davis-Besse Nuclear Pover Station, Unit No. 1, Operating License, Appendix A, i
{ Technical Specifications. j J
Davis-Besse Nuclear Power Station, l' nit No.1, Updated Safety Analysis Report, f l Revision 7, July, 1988. !
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