ML20205L163
| ML20205L163 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 10/21/1988 |
| From: | Drawbridge B YANKEE ATOMIC ELECTRIC CO. |
| To: | Fairtile M NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20205L166 | List: |
| References | |
| FYR-88-141, PC-222, NUDOCS 8811010498 | |
| Download: ML20205L163 (4) | |
Text
r-Tct: phons 1617) 872-8100 TWX 110-380-7019 YANKEE ATOMIC ELECTRIC COMPANY y
1671 Worcester Road, Framingham, Massachusetts 01701 October 21, 1988 PC-222 FYR 88-141 United States Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555 Attention:
Mr. Morton B. Fairtile, Project Manager Project Directorate I-3 Division of Reactor Projects I/II Referencest (a) License No. DPR-3 (Docket No. 50-29)
(b) 4.etter, USNRC to YAEC, Amendment 69 to Licensee No. DPR-3, dated July 22, 1981
Subject:
Request to Change Technical Specification 3.3.1. Tables 3.3-1 and 4.3-1
Dear Mr. Fairtile:
Pursuant to Section 50.90 of the Commission's Rules and Regulations, Yankee Atomic Electric Company hereby requests the authorization to make the following changes:
Proposed Change 1.
Remove the description of High Pressurizer Water Level in Section 2 Bases Page B2-4.
2.
Modify description of the Main Coolant System High Pressues in Section 2. Bases, Page B2-5.
3.
Remove the High Pressurizer Water Level trip instrumentation from Table 3.3-1 Page 3/4 3-2.
4.
Remove the High Pressurizer Water Level trip instrumentation from Table 4.3-1, Page 3/4 3-8.
Reason For Change The High Main Coolant System Pressure trip was installed at Yankee Nuclear Power Station (YNPS) in 1981 and presently replaces the High Pressurizer Water Level trip in providing primary protection for overpressurization of the Main Coolant System. This proposed change modifies the Section 2. Bases descriptions and operable instrumentation requirements to kkCM05000029 98 80EOEI A
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United States Nuclear Regulatory Commission October 21, 1988 Attention:
Mr. Morton B. Fairtile Page 2 FYR 88-141 be consistent with the above. Removing the High Pressuriser Water Level trip from the required operable instrumentation will allow greater operational flexibility during full-load operation.
Basis For Channe The High Pressuriser Water Level trip instrumentation was originally provided to ensure protection against Main Coolant System overpressurisation by limiting the water level to a volume sufficient to retain a steam bubble j
and prevent water relief through the pressuriser safety valves during an uncontrolled rod withdrawal or loss of load event.
However, the High Main Coolant System Pressure trip was incorporated into l
the Technical Specifications by Amendment No. 69 (Reference (b)), to provide additional protection against Main Coolant System overpressurisation.
.l l
j The High Main Coolant System Pressure trip has been credited in the loss
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of load and more recently in the control rod withdrawal safety analyses. The control rod withdrawal transient was analyzed using the CEMINI Code for predictirg plant pressure response and the COBRA-3C Code to evaluate DNBR.
j This methodology has been previously approved In conjunction with the reload l
analysis for YNPS.
i I
The reactivity addition rate in the rod withdrawal analysis was varied I
t between a minimum value of less than 0.1E-05 Ak/k/see and a maximum value f
of 20.0E-05 Ak/k/sec. All other reactivity feedback parameters were held constant. The minimum reactivity addition rate was determined such that the l
a an automatic reactor trip would not occur. The maximum reactivity addition rate is greater than the maximum reactivity insertion rate currently allowed by Technical Specification 4.1.3.1.3.
This was done to bound all allowable reactivity insertion rates.
I Only a narrow range of slow reactivity addition rates (between 0.1F.-05 l
and 0.2E-05 Ak/k/sec) caused a reactor trip by high pressure.
Faster
[
reactivity addition rates caused a reactor scram by high neutron flux.
In every case, the analysis has shown the response of the pressuriser water level is such that e loss of the pressurizer steam bubble or water relief through the safety valves will not occur. The DNBR calculation also yields acceptable j
results for this event.
i t
The results of the analysis described above demonstrate that the High L
Main Coolant System Pressure trip, in conjunction with the pressuriser safety t
relief valves, provides adequate protection against system overpressure. The l
Pressuriser High Water Level trip is completely redundant and not required to l
l provide overpressure protection when the High Pressure trip is operable.
L Thus, Yankee proposes to remove the operability requirement for the High l
Pressuriser Water Level trip and the associated description contained in the l
I Section 2 Bases.
In addition Yankee proposes to modify the High Main I
Coolant System Pressure description contained in the Section 2 Bases, by adopting wording similar to that contained in standard Technical Speeifications (NUREG-0452).
o United States Nuclear Regulatory Commission October 21, 1988 Attention:
Mr. Morton B. Fairtile Page 3 FYR 88-141 Safety consideration This proposed change is requestad in order to modify two descriptions within the Technical Specification, Section 2 Bases, to be concistent with present safety analysis, and to remove the operability requirement associated with the High Pressurizer Water Level instrument. As such, this proposed change would nott (1)
Involve a significant increase in the probability or consequences of an accident previously analyzed. The modification of two descriptions within Technical Specification Section 2. Basos, is an administrative change, and as such, would not involve a significant increase in the probability or consequences of an accident previously analyzed. Also, removing the requirement for operable High Pressurizer Water Level instrumentation would not involve a significant increase in the probability or consequences of an accident previously analyzed as the High Main Coolant System Pressure instrumentation will provide overpressurization protection for transient events.
(2) Create the possibility of a new or dif ferent kind of accident from any previou11y analyzed. The modification of two descriptions within Technical Specification, Section 2. Bases, is an administrative change, and as such, would not create the possibility of a new os different kind of accident from any previously analyzed. Also, removing the requirement for operable High Pressurizer Water Level instrumentation would not create the possibility of a new or different kind of accident as the High Main Coolant System Pressure instrumentation will provide an equivalent level of protection against overpressurization for transient events.
i (3)
Involve a significant reduction in a margin of safety. The a
modification of two descriptions within Technical Specification, Section 2 Bases, is an administrative change, and as such, would not involve a significant reduction in a margin of safety.
Additionally, the modification to the action statement of the High Pressurizer Water Level instrumentation would not involve a d
significant reduction in a margin of safety as the High Main Coolant System Pressure instrumentation will provide an equivalent level of protection against overpressurization for transient events.
Based on the considerations contained herein, it is concluded that there is reasonable assurance that operation of the Yankee plant consistent with the proposed Technical Specification will not endanger the health or the safety of the public. This proposed change has been reviewed by the Nuclear Safety Audit and Review Committee.
fJLe i
An application fee of $150.00 is enclosed in accordance with 10CFR170.21.
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,e United States Nuclear Regulatory Comunission October 21, 1988 Attention:
Mr. Morton 8. Fairtile Page 4 FYR 88-141 b
Schedule of Channe These changes to the Yankee Technical Specifications will be !aplemented s
upon comunission appro cal.
Very truly-y urs.
YANKEE ATOMI ELECTRIC COMPANY
- 7h B. L. Drawbrids Vice Prealliren and Manager of Operations i
JD/22.903 Enclosure COPHONWEALTH OF MASSACHUSETTS)
)ss MIDDLESEX COUNTY
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Then personally appeared before me B. L. Drawbridge, who, being duly sworn, did state that he is a Vice President and Manager of Operations of Yankee Atomic Electric Company, that he is duly authorised to execute and file the foregoing document in the name and on the behalf of Yankee Atomic Electric Company and that the statements therein are true to the best of his knowledge and belief.
k W
Helen D. Saaniacco Notary Public My Commission Expires August 29, 1991