ML17191B237
| ML17191B237 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 02/08/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML17191B236 | List: |
| References | |
| NUDOCS 9902160332 | |
| Download: ML17191B237 (4) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 170 TO FACILITY OPERATING LICENSE NO. DPR-19.
AMENDMENT NO. 165 TO FACILITY OPERATING LICENSE NO. DPR-25.
AMENDMENT NO. 183 TO FACILITY OPERATING LICENSE NO. DPR-29 AND AMENDMENT NO. 180 TO FACILITY OPERATING LICENSE NO. DPR-30 COMMONWEAL TH EDISON COMPANY AND MIDAMERICAN ENERGY COMPANY DRESDEN NUCLEAR POWER STATION. UNITS 2 AND 3. AND QUAD CITIES NUCLEAR POWER STATION. UNITS 1 AND 2 DOCKET NOS. 50-237. 50-249. 50-254 AND 50-265
1.0 INTRODUCTION
By letter dated November 30, 1998, as supplemented by letter dated January 8, 1999, Commonwealth Edison Company (ComEd, the licensee) submitted a request to relocate tne Technical Specification (TS) requirements related to Reactor Protection System (RPS) shorting links to the Updated Final' Safety Analysis Report (UFSAR). Specifically, the licensee requested changes to TS 3/4.1.A, "Reactor Protection System (RPS)," 3/4.10.B, "Refueling Operations, Instrumentation," and 3/4.12.B, "SHUTDOWN MARGIN Demonstrations."
Revisions to Bases Sections 3/4.1.A arid 3/4.10. B reflecting these changes were also requested. Shorting link removal is required under certain plant conditions as described in detail in the following paragraphs. Removal of the shorting links enables a non-coincident scram based on high neutron flux as detected by any neutron monitor including the Source Range Monitors (SRMs), the Intermediate Range Monitors (IRMs) and the Average Power Range Monitors (APRMs). The licensee requested these revisions to prevent inadvertent and unnecessary reactor scrams that may occur during normal refueling activities. While the shorting links are removed, the work that is performed is substantially curtailed due to the possibility of an inadvertent scram causing high pressure water to be forced through the seals in the control rod drives (CRDs). Accordingly, inadvertent and unnecessary scrams may result in excessive differential pressure on the CRD seals, with the potential for premature degradation of the seals. The increased frequency of damage to the CRD seals would result in unnecessary radiation dose to plant personnel due to more frequent maintenance.
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2.0 BACKGROUND
Dresden and Quad Cities Nuclear Power Stations are equipped with four SRMs, one in each
- quadrant of the core. During operation when the RPS shorting links are required to be installec;j, the SRMs provide control rod withdrawal blocks under certain circumstances, and indication to the control room. Each unit at each site is also equipped with eight IRMs. The IRMs, with four in each RPS trip system, provide a one-out-of-two taken twice reactor scram signal, as well as control rod withdrawal blocks and contror room indication.
The criteri.a for inclusion of a requirement as a limiting condition for operation in the TSs are set forth in 10 CFR 50.36. The criteria are as follows:
(1) installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant system pressure boundary.
(2). a process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a.
challenge to the integrity of a fission product barrier.
(3) a structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.
(4}
a structure, system, or component which operating experience or probabilistic risk
.assessment has shown to be significant to public health and safety.
As a result, existing TS requirements that fall within or satisfy any of the criteria of 1 O CFR 50.36 must be retained in the TSs, while those TS requirements that do notfall within or satisfy these criteria may be relocated to other licensee controlled documents, such ~s the UFSAR.
3.0 EVALUATION The licensee has proposed to relocate the TS requirements related to RPS shorting links to the UFSAR. Requirements forthe RPS shorting links are found in TS 3.1.A (Table 3.1.A-1, Functional Unit 1.a and 2.a, Note c), and Limiting Conditions for Operation (LCOs) 3.1 O.B.3, 3.12.B.1, and Surveillance Requirements (SRs) 4.10.B.4 and 4.12.B.1. References to RPS shorting links are also made in Bases sections 3/4.1.A and 3/4.10.B.
TS 3.1.A (Table 3.1.A-1) contains OPERABILITY requirements for RPS Instrumentation. Table 3.1.A-1, Functional Unit 1.a and 2.a, Note c, addresses requirements for OPERABILITY of the
. IRMs and APRMs, respectively, while in MODE 5. These requirements state that "unless adequate SHUTDOWN MARGIN has been demonstrated per Specification 3/4.3.A and the
'one-rod-out' Refuel mode switch interlock has been demonstrated OPERABLE per Specification 3.1 O.A, the 'shorting links' shall be removed from the RPS circuitry prior to and during the time any control rod is withdrawn. However, this is not required for control rods
- removed per Specification.3.10.I or 3.10.J." This amendment will relocate, in its entirety, the above requirement to the UFSAR.
LCO 3.10.B.3 contains a similar requirement for Refueling Operations Instrumentation. The LCO states that "unless adequate SHUTDOWN MARGIN has been demonstrated per Specification 3.3.A and the 'one-rod-out' Refuel position interlock has been demonstrated
.OPERABLE per Specification 3.1 O.A, the 'shorting links' shall be removed from the RPS circuitry prior to and during the time any ~ontrol rod is withdrawnCb>." Footnote b states that this LCO is "not required for control rods removed per specification 3.10.1 and 3.1 O.J." This amendment will relocate, in its entirety, the above requirement to the UFSAR.
SR 4.10. B.4 requires the verification "... within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> prior to and at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> during the time any control rod is withdrawn1b>that the 'shorting links' have been removed from the RPS circuitry unless adequate SHUTDOWN MARGIN has been demonstrated per Specification 3.3.A and the 'one-rod-out' Refuel position interlock has been demonstrated OPERABLE per Specification 3.1 O.A." Footnote b states that this SR is "not required for control rods removed per Specification 3.10.1or3.10.J." This SR will be relocated to the UFSAR. This is necessary to provide consistency with the modified requirement for LCO 3.1 O.B.3. The requirement for removal of the shorting links will be relocated to the UFSAR.
Specification 3.12.B, contains requirements for SHUTDOWN MARGIN Demonstrations. LCO 3.12.B.1 requires that "the source range monitors are OPERABLE with the RPS circuitry
'shorting links' removed per Specification 3.10.B." This LCO will be modified to read "the source range monitors are OPERABLE per Specification 3.10.B." This change is necessary to provide consistency with the modified Specification 3.10.B. The requirement for removal of the shorting links will be relocated to the UFSAR.
SR 4.12.B.1 requires verification that "the source range monitors are OPERABLE with the RPS circuitry 'shorting links' removed per Specification 3.10. B." This SR will be modified to require verification that "the source range monitors are.OPERABLE per Specification 3.1 O.B." This is necessary to provide consistency with the modified requirements for LCO 3.12.B.1 and Specification 3.10.B: The requirement for removal of the shorting links will be relocated to the
.UFSAR.
Bases sections 3/4.1.A and 3/4.10. B contain descriptions of operations with the shorting links removed. These descriptions are no longer necessary due to the relocation of shorting link removal requirements to the UFSAR.
Currentiy, the shorting links are required to be removed under conditions as stated above. With the shorting links removed, a non-coincident scram as detected by any neutron monitor is enabled. With the shorting links installed, the SRM high flux scram is bypassed and IRMs and APRMs provide coincident high flux scram capability. IRM and APRM coincident high flux scram capability provides the credited protection with respect to the safety analysis.
Additionally, the primary reactivity control functions during refueling are the refueling interlocks and adequate SHUTDOWN MARGIN (SOM). The refueling interlocks are required to be OPERABLE per TS 3/4.10.A, "Reactor Mode Switch." Although the SOM may not have yet been demonstrated in MODE 5, SOM calculations would have been performed and, along with
- procedural compliance for any CORE AL TERA TIONS, would provide assurance that adequate SOM is available. Without removing shorting links, IRM and APRM operability will continue to provide scram protection with coincident logic for any significant reactivity excursion as credited in the safety analysis. The SRM channel high flux scram (with shorting links removed) provides
. only an uncredited backup in MODE 5. Due to the required operability of the refueling interlocks, the continued capability of the IRM and APRM coincident scram, the SRM high flux*
scram not being credited in the safety analysis, and procedurally-assured adequate SOM, the relocation of the shorting links removal requirement does not significantly affect safety.
Furthermore, the requirement for removal of RPS shorting links does not meet any of the criteria contained in 10 CFR 50.36 for requirements to be included in TS. Therefore, the changes, as des.cribed above, to TS 3.1.A (Table 3.1.A-1, Functional Unit 1.a and 2.a, Note c),
3.10.B.3, and 3.12.B.1; are acceptable. The changes, as described above, to SRs 4.10.B.4 and 4.12.B.1 are also acceptable as these changes provide consistency with the modified LCO requirements. Changes to Bases sections 3/4.1.A and 3/4.1 O.B that remove references to the shorting links are appropri~te and acceptable. Any changes to these requirements located in the UFSAR will be adequately controlled by the provisions of 10 CFR 50.59.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois State official was notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendments involve 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 proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (64 FR 1032). Accordingly, the amendments meet 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 amendments.
6.0 CONCLUSION
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 amendments will,not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: L. Burkhart Date:
February 8, 1999