ML19345A657
| ML19345A657 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 04/27/1962 |
| From: | Bryan R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML19345A655 | List: |
| References | |
| NUDOCS 8011240451 | |
| Download: ML19345A657 (3) | |
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H/2ARDS ANALYSIS BY THE RESEARCH AND POWER REACTOR SAFETY BRANCH DIVISION OF LICENSING AND REGULATION
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IN THE WTTER OF YANKEE ATOMIC ELECTRIC COMoANY PROPOSED CHAILS NO. 15 g =;
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Introduction Parsuant to the provisions of paragraph 3. A. of License No. DPR-3, as amenGd, Yankee Atomic Electric Company in Proposed Change No.15 dated
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Janua:,/ 11, 1962, and in an amendment thereto dated February 1,1962,
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requested authorization to revise Maintenance Instructions 506 E2 and 506 Eh and, in addition, requested that item D.2.a.(2) of the technical specifications he amended. The Maint<.:ance Instructions presently con-
+1.3 tained in the license application were prepared before the initial
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loading of the reactor, and Yankee would like to revise these in the s..
light of the experience which was gained during this loading. Yankee muld also like to revise item D.2.a.(2) of the technicel specifications as a result of their experience to date. It is !cnkee's opinion that they were delayed excessively during the initial core loading by the
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recuirements of item D.2.a.(2) of the Technical Specifications. They also believe the loading procedure required by this item is not appropriate for refueling at the end of Core I life.
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l Eircurcion
'cle hr.ve reviewed the Maintenance Instructions which Yankee has proposed and have conclud';d that they cre adecuate except in' regard to two items.
l In Section III 6 cf Maintenance Instruction No'. 506 Eh, Yankee has proposed that if an unexpected increase in the count rate by a factor of a new fuel essembly or' removal of a entrol rod, the fuel loading
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twc on two of three instrur.entation channels cccurs after addition of cperation vill be suspended until the situation can be reviewed by plant technical supervisory personnel. In our opinion, an unexpected increase in count rate by a factor of less than two could be of sufficient l
significance that the loading operation should be suspended. It is E:
also our cpinion that, with the proposed method of loading, an -
instrument channel may be near an empty quadrant of the core and pro-vide little useful infornation. We, therefore, believe that at least two cht.nnels of cource range nuclear instrumentation should be in cperation and in a position to monitor the neutron population and its time variation at all times when core loading is in progress.
Accordingly, we believe that the first sentence of Section III 6 should be changed as fellous:
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, "If a significant unexpected increase in the count rate occurs on any one channel or if an unexpected increase in the count rate by a factor of two on two of the three channels occurs after addition of a new fuel assembly or renoval of a control red, the fuel 1:ading operation will be suspended until the situatien can be reviewed by plant technical cupervisory personnel."
We also E cya that the first sentence of Section III 2 of the Maintencnce
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Instructicn a.ould be revised to state, "At least two of. the three source range channels of nuclear instm mentation ust be in operation and in a position to :enitor the neutron population and its time variation in the reactor whenever the core geonetry is being changed."
Yankee has also proposed that iten D.2.a(2) of the Technical Specifications be amended to read as follows:
E "During the refueling operation a record vill be made of the neutron
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count rate before and after any change in core geonetry. If an unexpected increase in the count rate by a factor of two on two of
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the three channels occurs after addition of a new fuel assembly or removal of a centrol rod, the fuel loading operation will be suspended until the situation can be reviewed by plant technical supervisory personnel. If necessary to establish the :.r;ncewn r.argin of the core, a single control rod will be withdrawn using the l-manipulator crcne and regulated by a plot of control rod position vs.
inverse count rate rultiplication. Using the inverse count rate data obtained in this manner, the shutdown margin will be calculated.
If these calculatiens indicate that there will be less than 5%<.k/k shutdcun with all control rods in crtad in the fully loteed core, the boren concentration will be increased to provide the required 5%4 k/k shutdo m margin."
~4e believe, as in the case of Sectien III 6 of &intensnee Instruction Uc. 506 Ih discussed above, that Yankee's : tate..ent regarding the unexpected change in count rate which would necessitate suspension of the loading operatica should be amplified. Accordingly, we believe that the proposed new iten D.2.a.(2) of the technical specification shculd be changed te read:
"If a significant unexpected increase in the count rate occurs on any one channel or if an unexpected increase in the count rate by a factor cf two on two of the three channels occurs after addition of a new fuel assenbly er removal of a control rod, the fuel loading operation will be suspended until the situation can be reviewed by plant technical rupervisory personnel." We believe that with this change the proposed a :enhent to the technical specifications is acceptable frcm a safety standpcint.
Conclusion Subject to the above conditions, it is our opinion that the revised Maintenance Instmetions and the change in technical specifications proposed by Yankee do not represent significant hazards considerations hh
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n not described or irplicit in the license application, as amended. In addition, we have concluded that there is reasonable assurance that the health and safety of the public will not be endangered by operation
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of the facility as proposed and as modified.
Orif=1 siped 4i=
by Rdit H. Eri:a
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Robert H. Bryan, Chief
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Research & Power Reactor Safety Branch
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Division of Licensing and Regulation
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'412 Cr:
APR 2 71992 Date.
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